Cant remeber this films title

[lizzard arm movie?]

I seen this movie a few years ago during the summer on like monster vision or USA network

This guy is like in his 20's he is a scientist working on limb regeneration his stepmother i think is having an affair with this guy and they murdered his dad or something anyway he runs away and ends up losing his arm he regrows it but it can detach itself and kill he takes up refuge with people in the sewers he falls in love with this girl there and then something happens where he is caught and the girl is caught and his mom/step-mom ends up taking over the girls body and she plans to put her lover into his body i can almost remember everything but the title its was made between 1985-1995 i think

[Andrew]

"Severed Ties" (1992)