I have read your last response, albeit it is not showing up on the posting for some reason.
I suspected that you had Thrush (candidiasis), and because of that I suggest your girlfriend will need to get checked out to make sure that she does not have it also.
If one of you has it and the other one is treated, you can still get it back again when you have sexual contact.
Ensure that you have a healthy and well balanced diet and cut out or cut down on sugary foods and drinks. Too much sugar in the diet encourages yeast growth. If you continue to get the problem, ask your doctor to check your HbA1C levels by having a blood test to check for glucose intolerance, pre diabetes, or diabetes. People who have diabetes can be prone to getting fungal infections.
You need to get back to your doctor and ask for an skin swab to be done to be sent to the lab for analysis.
Follow the advice I gave and also ensure that you keep the area clean. Also wear clean cotton underpants every day.
It may be that your girlfriend also needs treating at the same time as you are. If you are getting the problem only after having sex, it may be a good idea for the two of you to get a swab from the genital area to be analysed for any bacterial or fungal problems.
One partner may have a problem and not know about it, but can infect a sexual partner.
Having any type of broken skin can lead to further infections. And if you are having oozing spots, you should get back to your doctor. It may be that the cream that you have been prescribed is not the right one for your problem and the doctor can prescribe a different one.
If you both have a fungal infection, that would need to be treated with antifungal medications. You can purchase antifungal creams for use specifically on the genitals from the pharmacy without a prescription. You can also purchase antifungal capsules to take by mouth from the pharmacy without a doctor's prescription. This is usually a one singe dose capsule. If it is a fungal problem that you have and it persists, the doctor can prescribe a stronger and a longer course of treatment if required.
The capsules are Fluconazone and Itroconazole. Ask the pharmacist. Preferably it would be better to get a swab of the are analysed by the lab to find out if you do have a fungal problem before using this type of medication.
I suggest that you ask your doctor to take a swab of the area for it to be sent to the laboratory for analysis.
If the condition is interigo it may be that you have an allergic reaction to what your girlfriend is using - soap, perfume, bath or shower gel, or even the detergent from her clothes.
Make sure that you use a good sexual water based lubricant when having sex to avoid any friction. If you use condoms - only use the latex free ones as you may have an allergy to latex.
It may be a good idea for the two of you to get checked out in case your girlfriend has any fungal or bacterial problem that you may be passing on to her or getting from her. If a bacterial or fungal problem is very mild there may be no symptoms.
Always wash your hands after using the toilet and before touching your penis. Always wash with water after having sex. Use a soap that has the same pH level as our skin or you can purchase an emollient to use instead of soap. Do not use normal soaps, bath or shower gels; these will dry the skin and aggravate your condition.
As a home remedy after washing and gently drying, you can apply natural set yogurt to the aggravated area. You can use this as long as you need to. It will feel cold and will help to soothe any soreness and heat.
Hope you get things under control soon.