The only approved medical use of DMSO is for interstitial cystitis of the bladder, I think, but that's because there's no big money to be made by drug companies on it.

My favorite DMSO stories:

1.
Many years ago, a friend of my Dad's had very painful gout. The pills take forever to work, so Dad went over to his house and started painting his toe with DMSO. Within minutes the pain was decreasing, and in half an hour the swelling was lessened enough that he could walk without too much discomfort.

2.
Our dog developed a tumor on her front leg. In removing the tumor, the vet had to take so much skin that there really wasn't enough to pull together around the leg to stitch up, but the vet did it anyway, In a couple days the leg was clearly beginning to develop gangrene from the strangulated circulation, so Mrs. Fusion (an M.D.) removed the stitches, and then I mixed up two parts DMSO with one part 30 ppm nanosilver solution (PATIS 30 brand), put it in a baggie and soaked the leg it in for several minutes. Then we treated the open wound with calendula gel and bandaged it up. The next day the leg looked much less gangrenous, but we repeated the DMSO-silver treatment once more, and thereafter just rebandaged every day with calendula gel. It took a couple months for new skin to grow over the wound, but in a year or so all the fur had grown back and you couldn't tell anything had happened.