I Have Recently Started To Stretch My Foreskin As I

I have recently started to stretch my foreskin as I only used condoms before and never pulled foreskin back. Over period of few weeks I have managed to pull it back, but it never comes back up on its on and sex is a bit painful. Do I need any cream or lube? Or in time i should be able to enjoy sex? Last 2 times I couldn't even cum