I Have Had What I Thought Was A Yeast Infection

I have had what I thought was a yeast infection for about a week or 2 now, mil itching and burning around my clitoris - 1 small spot was particularly painful when touched. I started using Mobistar 7 topically on the area and symptoms started to get better but tonight I noticed an ulcer looking area on my clitoris about the size of a pea - I'm worried it could be herpes but I've beer had symptoms line this before - is there anything else it may be?