Reddish Penis, Dry Lump On The Foreskin. Using Daktacort Ointment. Should I Be Worried About Sexual Activity?

hi, basically for the last 6 months i have had a red penis tip, it seems to calm down but get worse when i masturbate or have sex, after any sexual activity it remains red for a while and goes a little dry, i also have a small bump on the under side of my penis on the foreskin , it is kind like a tiny crater, it does not hurt but again seems to get worse during sexual activity, i have seen my gp and he has given me some daktacort ointment which seemed to get rid of the redness however it is no longer working, i have just got a new girl friend and i am nervous to do anything because of this, do you know what this could be?