Accidentally I discovered that an extremely hot bath (or latterly a hot shower) takes the sting out of the burn . Painfull but effective .
Got insanely burnt in Florida in March, after severely underestimating the not particularly hot sun there. Bought a shedload of aloe vera extract, which made things much better within a couple of days. The locals clocked me as British from 500 metres. Lobster ****.
Try heating some needles and then push them down the back of your fingernails It won’t cure the sunburn but it will take your mind off it!