What Causes Redness In Vagina Along With Curdled Milk Discharge?

I had sex for the first time in years last sunday. unprotected with my husband who i had been separated from. I used ky warming gel. I also started using antibiotic drops zymaxid on tuesday for pre lasik surgery. by weds morning my outer vagina was read and burning. by the end of the day i had disgusting curdled milk discharge, no smell. I have a dr apt on monday, but was just curious if this could be caused from the antibiotic drops or perhaps the lubebrcant? or god forbid, an std? I havent had a yeast infection in 20 years or more!