What Causes A Small Puncture On The Arm That Bleeds Often?

i have a tiny hole the size of a pin prick on my tricept that is bleeding ... it only bleeds when after i swim or shower i run the towel over it and break the scab for 99pc of the day it is just a tiny red dot that seems to be trying to scab but ... i swim everyday for hour, no fever no other symtoms except i have been sleeping 10 hours a day and getting up at noon not sure why tired from swimming or emotions i am 55 yr old male