What Do Ulcers Around The Urethral Opening Indicate?

I have a couple of ulcers near my urethral opening. I’ve been married 14 years to the same man and we have not had any sexual activity in the last six months. Also, this started after beginning a strong antibiotic for staph on my index finger next to the nail bed. Initially I had uncomfortable itching and assumed it was a yeast infection, which is common for me when taking an antibiotic. Then a couple of days later I noticed that it was extremely sore when I wipe myself after urination. At first I thought that I had been wiping too aggressively at the onset of what I thought was a yeast infection, which by the way I did treat with an over the counter med. I used a hand mirror to examine myself today after I got some bright red blood on my toilet tissue, which I only blotted because it is too painful to wipe at this point. Anyway, when examining myself I saw two small ulcers. I’ve never had anything like this and I’ve only had two partners my entire life. My first husband of 15 years and second husband of 14 years. I am 54 years old. What could this possibly be and what would be the cause?