Had unprotected sex about five weeks ago, and got itchy rash on my penis. What did she give me?

No way to know. If you have a problem after unprotected sex, you should get seen, examined and treated appropriately. The risks are too high. Use protection! now you know!
Maybe nothing. It could be an allergic reaction to something, such as a spermicidal gel that she may have used, or a direct irritant reaction. If you really suspect an std, see a doctor and get tested. And i hope you learned your lesson about unprotected sex!

Related Questions

I had unprotected sex and now I have 3 red dots on head of my penis and a itchy red rash around the shaft and base of my penis is this a std?

Probably not. None of the stds does that. It's probably a skin issue. Eczema is common. Read more...
STD? maybe? Does your partner have any lesion / discharge? This is not something you want to ignore. You should see your md asap for a proper exam of your lesion. The correct diagnosis maybe something simple as allergic contact dermatitis not related to sexual activity, or an infection by an organism known for "impersonating" other illnesses(syphilis). This would require antibiotics. See you md to be safe. Read more...