How to lessen sunburn pain and redness?

I was out with family swimming...I didn't apply enough sun screen to my face,chest,and shoulders. The swim suit line is SO clearly seen..It happened a few hours ago and it still hurts like hell. And I'm going AGAIN with my friend. I'd hate to cancel on her because of a sunburn,but I don't want to be sitting watching her play around. Any tips for less reddening or lessening the pain?