Will the area itch/burn for a day or two before the cold sore actually appears?

I drool in my sleep so i woke up one morning and the corner of my mouth was wet. When it’s wet bacteria will form. At that time i wiped my mouth dry and scratched it cause it was itchy (Bad move). Guess what happened? It turned all red, got itchier and started to burn! I looked in the mirror and it was too late, the bump has formed into tiny blisters. I thought it was no big deal so i used soap on the area and left it alone. Next day it looked worst…. but i still ignored it thinking it’ll go away by tomorrow. Another day past and this time it started to scab. Since cold sores and angular cheilitis can look the same and appear in similar areas I was really scared and actually assumed it was a cold sore. I went to the doctors next day and asked him to check it, no blood test or anything just a look. He seemed very unprofessional, looked for 4 seconds and said hm… right when he was about to speak i just had to ask him IS IT A COLD SORE DOCTOR??? i guess i should of let him tell me… now he thinks i get them and will just give me any answer. He said yes it’s a cold sore i will prescribe you a cream. I was so upset that day because i never had herpes and thought no girls would ever date me. I told my mom what happened and she said no silly, it’s just from drooling. She was saying how the doctor was unprofessional and didn’t even examine me enough to prove that it was really a cold sore. anyways…. as i was researching up on the net i found angular cheilitis. I was like hey what if it’s angular cheilitis instead of a cold sore? Doctors can be wrong too their human just like us.

So my question is... is it true that you will feel burning and itching of the area for about 1 - 2 days before the cold sore actually appears? Because what i have at the corner of my mouth did not itch or burn a day before at all. It was perfectly fine till morning it started to itch and burn when i scratched it and turned into blisters.

if it isn't a cold sore i probably wasted 35 bucks on a prescribed cream which didn't really help at all.

[Dr_Aparna]

Hi,
Cold sores present as small, painful, fluid-filled blisters on a raised, red area of your skin, typically around the mouth.  
Pain or tingling, called the prodrome, often precedes the blisters by one to two days. They usually last seven to 10 days. The blisters that have formed, then break and ooze. A yellow crust forms and finally sloughs off to uncover pinkish skin that heals without a scar.

Cold sores generally clear up without treatment in seven to 10 days.  Topical lidocaine or benzyl alcohol (Zilactin) applied on the sores may help relieve symptoms.
Using an antiviral medication may modestly shorten the duration of cold sores and decrease your pain, if started very early.
ref:http://www.mayoclinic.com/health/cold-sore/DS00358/DSECTION=treatments%2Dand%2Ddrugs

This could be an allergic reaction or a fungal infection associated with angular cheilitis.
You can apply an anti-fungal cream available OTC or a 1% Hydrocortisone ointment on the lesions till they clear up.