well if the bump was not on his penis before and it is now, it would be a concern...call your doctor and describe it to see...

see if more bumps come up on him before having sex...

I see no choice but being honest with him...I know this is hard but you are in an adult relationship with him and it means having these types of conversations. hopefully he cares enough about you to understand.

welcome to psych central. you will find that we have several forums where you can post about your concerns and receive feedback from other members. you will get a lot of support here. again, welcome