How long have you been using the over the counter cream and how often do you use it?
A cream like Lamisil AT will generally require a shorter time. Be sure to follow the directions on the box.
Lotrimin if that is what you have purchased will also work. It may just take a bit longer.
It is very possible that you spread the fungal infection from your feet to your penis. It is quite common.
Here is a link to the Mayo clinic that will detail prevention and other information.
If over the counter treatment doesn't work, just call your doctor. It is really no big deal and is quite common.
I hope this helps, T
I have sent this post to a moderator, so they can help you with all your questions.
Best wishes and thanks,