What Causes Discoloration On The Penis?

Hello, I would first like to say I am very dis proud to announce my potentially bad problem but after several days now of searching what may be wrong with me and worrying i have to ask - I recently have noticed some discoloring with my penis and im afraid ... The best way i can explain what i see is that mainly the head has discoloration, it seems to have lost its natural color and there are barely visible yellowish spottings on the head region . In addition, i can more clearly tell a noticeable color difference at the very bottom of the head; more of a pinkish/purple color (not on my shaft) but i do not feel discomfort from pee-ing as well as no itching or such . Im unsure if this helps but there is also a clear what appears to be purple bruise on my shaft . Im curious to know if drinking can be related or mainly if this is curable ...