Hello..i Am A 17 Year Old Female Who Is Slightly

Hello..i am a 17 year old female who is slightly overweight. after laying in the sun yesterday without sunscreen, my stomach is badly burned. i have stretch marks on my stomach that are now even redder and very enflamed. every time i stand up the sunburn stings because the skin on my stomach creases and bends when i sit down and stand up. Is this anything to worry about and what should i do?