Painful thigh blisters

Hello. I'm 29 year old sexually active man. I had really good and regular sex life until my sex life turned into a nightmare.
I don’t know how to describe this.
About a week or so, I got these really painful blisters on my left thigh region and around my testicles.
I thought that the cause could be some skin allergy on some material of pains or underwear and didn’t pay too much attention on it.
But I was wrong. These blisters ruptured on about the 5th day and formed wet ulcers that are terribly painful to touch
I don’t know what to do because I'm suspecting on some sexually transmitted disease. Does anybody knows what this could be?

I wouldn’t go so far and call it a sexually transmitted disease but you are definitely suffering from sexually transmitted virus which will stay in you to the rest of your life.
Your virus is called herpes simplex and it is causing genital herpes, condition accompanied with thigh and testicle blister.
The infection is transmitted during sexual intercourse or by other intimate contact with the genitals, mouth, or rectal area. Once you're infected, the virus remains in your body for the rest of your life.
The blisters often appear in groups, or clusters. Some people only get one blister sometimes.
Herpes is very contagious, but symptoms do have to revel them self
Immediately- outbreaks can occur from physical or emotional stress, tight clothing, intercourse without enough lubrication or the stress of an illness.
One more sad news for you- genital herpes can not be cured. But in most cases all the time it “sleeps” in your body and cause no complications what so ever!