My 4 yr old min Pin hooked to dog in heat several times. His penis is now red swollen and won't go all the way back in. What do I do for him?

Just let him be unless he can't urinate and seems to be uncomfortable than you would need take him to a vet But that happens in them type of dogs so i wouldn't worry too much we had a Chihuahua the same thing happened with him many of times when our female dog came in heat..