Hi, I am Dr. Shreyash Mehta, am a MD Community Medicine
I can answer your query
As you told that you had intercourse 10 days ago for 3 hours and now you can not hold erection.
At present as you told that you are getting mild erection in the morning implies that you are erection is normal and no
nerve injury to it.
You told about bits on you
scrotum, can you still explain further. I thinks they might be some local abrasion following you 3 hours of intercourse. Or it may be
skin tags which all male have on their scrotum.
The lack of erection may be mental issue. You might not be getting the stimulus of erection when you are with your wife/partner (the one you mentioned whom you had intercourse).
So just check whether you are able to get erection thinking/seeing other female.
Also there may be some stressful situation due to which you are not able to have proper erection.
Having erection has a mental as well as physical aspect.