What was that little known 80's horror/romance movie flick?

I'm trying to remember the name of an old movie that wasn't very good or popular, but was still a fun flick because it captured the 80's culture style so well.

In this movie, the lead actor is a guy who totally looks like rocker/greaser (sexy mullet hairdo, tank top, beefcake). He falls in love with this girl, except there is one problem. He has recently been possessed by some kind of demonic spirit. His feelings for this girl are growing more towards love, but every time the romance escalates, the demon inside him starts to make his body change form. The special effects and make-up on his face are a bit humorous even for the time when the movie was made. Usually the guy would try to run away every time this "little problem" happened, because he loved the girl so much and he didn't want to do something crazy like accidentally tear her head off while making love!

At the end of the movie there is a big showdown between him and another nerdier man who also seems to have discovered a demon within himself. This guy becomes the arch-villain when it's discovered that he is far more powerful than anyone ever imagined. In the end they defeat him, and he even manages to cleanse his soul of the demon. And then it's a happy ending because he can finally make love to his girlfriend.

Anybody know what movie this is? When I watched this movie as a child, he sort of reminded me of a vampire/wolfman because of the way he would start to "wolf out" every time he started making out with a girl.