How do i know if i have had an aphthous ulcer on my clitoris?

Be checked: Ulcers in the genital area need to be properly evaluated, could be as benign as little trauma to siphilis or even cancer. Please go see your doctor.

Tough answer: First for you to have an aphthous ulcer there, you had to have oral sex with an infected person. The ulcer is a "cold sore' that is self limiting and is not genital herpes. Only way to verify it would be to be tested. A swab will be taken of the ulcer by your ob/gyn and cultured. There is no other way to determine the answer.