Help with curing sunburn? Does vinegar do anything?

Yes... ...It makes you smell like a salad. Does it do anything for the sunburn? No. Sunburn is properly treated like any other burn, with cold compresses and an antiseptic cream such as silvadene (silver sulfadiazine) or bionect. And take this as a warning that mr. Sun is our friend, but we have to respect his power; wear a good sunscreen lotion (spf 50) next time.
Simple Care. Sunburn is response of the tissues to injury from solar radiation. It is simply inflammation which means increase blood flow to the area to promote healing. Do not use ice as this can injure already injured skin. Cool water soaks can help as can taking anti-inflammation medicines like Motrin or advil (ibuprofen). Avoid any further damage as this can cause scarring . Good skin cream applied daily/gently helps.