Yeast infection (thrush) isn't very common on the penis, and is especially rare unless a sex partner has a vaginal yeast infection. Other fungal infections are possible. But if you had any kind of yeast/fungus, the standard treatments usually are highly effective. So if you were given proper treatment (which I cannot judge, since you don't say what creams were prescribed), most likely the problem is something else. I cannot begin to guess at other possibilities; any of the many things that cause skin rash anywhere on the body sometimes involve the penis. In any case, you can be sure it is no STD--and that's where my expertise and advice ends. Seeing a dermatologist would make sense as the next step.
Good luck-- HHH, MD
You don't have an std. Keep in mind this an std forum. Only a limited number of questions are taken a day. Thrush isn't an std either, but I hope it clears.