You can try to put him into the sink and run cool water on his penis. If the hair is keeping it from retracting you can try a little KY jelly to the tip. If its been exposed to the air for a while it might just be dry and stuck to the hair. Either "method" will work. This is a serious issue and I cannot believe a vet tech would have told you to let him "chill" for an hour or two!
When it happened with one of my boys I used the sink sprayer to really get him wet. Poor little guy shivered afterward but it went right back.
Is your female Pit in heat?