As far as I know you can't. The skin has been burnt and the body needs time to recover from it. All I can suggest is that you apply moisturiser or after sun lotion and hope you don't peel too much.
Vinegar stinks, but it takes the sting out of your sun burn. Also shaving lotion is good.
Double up on Viamin C and your liquids and it wouldn't hurt to take some Vitamin E for the skin as well.
You need to get fluids back in to moisturize the skin - possibly keeping you from peeling or blistering.
You will probably be down with your sundburn for a few days at least.