Some of these pictures and descriptions may give away plot details that you might not want to know before watching the film.
This is a low-budget English horror movie about a drug-addict prostitute in a trailer park brothel named Carly whose life gets even worse after a snake bites her. The writers throw in every snake-related thing they have ever heard about - vertical pupils, fangs, spitting venom, scaly skin that sheds, and a big rattle on her tail she shakes when she's angry. OK, not the rattle, but all of the rest is there, and more: snakes grow out of her head like they do with the mythical Medusa and she can turn people into stone.
After bringing her back into the brothel life she tried to escape from by feeding her drug addiction, Carly's pimp brings her to a customer who shows her his pet snake, a Ball Python named Alexis that he tells her is special. As they're having lap dance chair sex, the snake bites Carly on the thigh.
We find out just how special the snake is when Carly starts turning into a snake - her skin peels off, her pupils become vertical, and she grows fangs. Strangely these things are not permanent, they come and go. Probably so she doesn't terrify the other hookers and johns, and also so we can't see how bad the special effects are for very long. Carly also discovers that she is very strong, capable of breaking a man's neck and tearing out his throat with her teeth. She also has venom she can spit in someone's face that will burn it like acid.
After she starts changing into a snake, Carly goes back to the snake man's house to figure out what's happening. She finds him dead and meets a woman named Alexis, who is some kind of witch with a group of prostitute cult members. Alexis gives Carly a cocktail called a "snake in the grass" and encourages her to accept her changing body, kill her pimp, and turn the madam of her brothel to stone. Finally, Alexis and her squad of hookers welcome Carly as Medusa, their serpent queen, and snakes grow out of her head.