Will skin in the hips be stretched after removing hip implants?

This will depend on how large of hip implants are placed. If they are very large implants and the skin becomes very stretched, it may not completely contract. However, if the implants are more modest sized, then there is a good chance that the skin will contract. The implants get placed deep on top of the TFL and thus unless you are very thin, there should be a thick flap of tissue which is likely to contract.