Do you nead to have a smear test after a recently done MRI test for a slipped disc. wouldn't anything abnormal shown up in that?

Yes, you still need to have a pap smear. An MRI done to check for a slipped disc is not testing for the same things that a pap smear tests for, nor is it looking at the same areas of the body.

A pap smear is designed to find changes in the cells of your cervix. These cells are very small, and such changes would not show up on an MRI.