Have you considered taking birth control? It will help reduce the acne because cystic pimples (the painful ones) that you are getting are usually hormonal acne. Tea tree oil doesn't do jack squat, it just keeps anymore bacteria from getting into the affected area. Try a gentle facial cleanser (the best one that is inexpensive and works great for treating acne would be the Cetaphil daily cleanser). Cleansers are better than the regular face washes since it actually purges the pores.
Peels honestly aren't worth the time because most people that try them at home end up chemically burning their skin (sometimes pretty bad).
For scarring try lemon juice every night before you go to bed, this will take a while to fade them but it will work. You also need to expholiate every day, use a gentle scrub for 3 days (st Ives green tea scrub works great for acne) and then the 4th day use an abrasive scrub (St Ives apricot scrub is great for acne as well) and just make that a cycle. Then you will need to use an acne treating toner morning and night (Stridex sensitive skin acne treatment pads work great and are inexpensive).
Most important thing is to keep a routine. Stick to that routine and it should all clear up. If you have anymore questions feel free to ask me.
Go to acne.org and order the regimen! Research the video reviews on YouTube, the facts are crazy and it has a 99% success rate. It works for all skin types and it got rid of my scarring completely
How severe is your acne? Is it just the 3 awful spots or is there more? Stress to the body can be a large factor in a flare up of acne. Changing sleep cycles, foods and stress levels can cause your body to respond in strange ways, so your move to a new country could have helped worsen the problem. Cystic acne is an inflammatory condition that I know well, having experienced horrible adult acne on my face a year or so back. If your acne is not too severe, I would suggest the following. Use only gentle cleansers. Cetaphil for sensitive skin is loved by many acne sufferers, I used a gentle and all natural face cleansing regime called Karen Farley, made in New Zealand where I live and available for purchase online, but Cetaphil is fine. Stop using tea tree oil it is too drying and harsh especially undiluted, it will irritate your skin stressing out your pores, which need to heal after a pimple and need gentle treatment. If your acne is cystic and painful I would highly recommend going to the doctor and going on a course of antibiotics. Antibiotics in conjunction with a gentle cleanser and moisturiser can work very well on moderate cystic acne and help fix the problem before it becomes too severe. Bear in mind that you must be patient and give the antibiotics time to work, you may be on them for a month or more. Take a supporting probiotic to protect your gut while you are on the antibiotics, ask your doctor what is best to take. I would also highly recommend taking a liquid zinc supplement (here in NZ I use Clinicians zinc, about 5 drops in a glass of water a day, but check with your doc). The zinc helps significantly with the scarring and purple marks.
For me, dropping all the harsh cleansers with salicylic acid etc in them was the best thing I ever did for my acne prone skin. Keep it gentle as possible is my advice and stay away from drying products. Cleanse twice a day only as over washing your skin will aggregate the problem, you skin needs to regain its natural oils and balance.
And finally, the most important part which you probably already know, is try very, very hard not to squeeze and pick at your cystic pimples, it will make them 10 times worse and much more likely to scar, also it hurts the pore even more and the pores around it which is why you get a group of pimples in one close area. If you absolutely must pop a pimple make sure it has a head on it do not touch it if it's blind you will only cause scarring . Use an alcohol/sterile wipe to cleanse the area, sterilise a needle and gently pierce the spot causing the least amount of damage to the skin as possible. DO NOT SQUEEZE IT after you have open the pore but with cotton buds, push DOWN on the skin around the pore with light pressure and gently let the gunk out. If the gunk turns clear or bloody STOP, as you do not want to cause further damage. Wipe the spot again gently with a sterilized wipe or pad. Please note, this is my advice from vast personal experiences with cystic acne. It is best not to pop or squeeze spots if possible.
If none of this helps and after a couple of months your acne is getting really bad please have your doctor refer you to a dermatologist, or, depending on the practice in your country, ask your doctor if Isotrentanoin is a necessary medication, this medication is a last resort as it can have some heavy side effects and should only be used if your skin is really bad and nothing else has worked. I finished a course of isotrentanoin 3 months ago and now I have no spots at all. I had to take it for 6 months.
Drink plenty of water and eat lots of healthy whole foods. Treat your skin mainly from the inside out.
Hope this helps and good luck :-)