Just like everyone has indicated, you need sunscreen and you need to treat this as soon as possible. Another way is for you to avoid the sun like a plague and use a good sunscreen with an higher spf. This reduces the sunburn a great deal. You can read more from this blog here. http://peachykemog..com/2013/06/your-skin-and-sun.html
please share with us whatever works for you as you might just be helping someone out.
Cheers