There was a previous post that warned of a sunburn-like reaction to 90% DMSO applied to her dh's lower back. It was probably a bit too strong, or the pores of his skin were open (from heat, sweating or a warm shower).
I have googled it, and there are references to DMSO as a remedy for burns and sunburns. Proceed with caution. You might have better luck with fresh aloe, lavendar, St. John's Wort, tea tree oil, chamomile, green/white/black tea, acv, coconut oil, cool baths...
Remember, it is important to soothe the burn, relieve the heat, and reduce the inflammation. So, hydrate, use a topical, and take something anti-inflammatory by mouth.
I am sorry for your "owie".