Painful the day after sex. Please help!!!

Madison

I’m 20 years old. My SO can normally stretch me out down there but after sex I have this inflammation down there. It normally happens the day after. What can I do to help with that? Idk if I’m not getting wet enough or he’s to rough but it is painful. Neither of us have a STD. I don’t have insurance and I’m recently on my own, so I can’t go to the doctors. Any suggestions???