rear end sliding

I have a front wheel drive 95 Galant. I week back i ran up on a curb in the snow. It made a super loud thud and then both right side tires blew. Now after putting some used tires on it there is an issue when pavement is dry drives ok. Then when its wet any thing over 35 mph and the back end keeps sliding all over the road where I cant handle the car at all. What can be wrong that it would only do that in the wet pavement. It is a really bad sliding. It has slid me across several lanes at 40 mph.

You should get someone to check the rear suspension. Sounds like you bent something pretty bad and if you let it go you will eat tires like crazy on top of the problems you already have. Anytime you have a hard hit like that you should have someone look at the car.