I'm 76 year old man living in Sydney Australia. I had surgery on my left hand 10 years back and removed the contraction which had the ring finger at 90° to my hand, surgery was successful and hand has returned to normal.
3 Years back I noted growths were commencing on my RH, I work full time and use keyboards for typing and that new growth was going to stop me working. So I commenced to rub DMSO into the area as I already very good results from using DMSO to free up my body from age related changes.
The DMSO on its own appeared to halt the growth from expanding but did not reduce the growth.
Dr Brian Ardis posted work using nicotine patches and I was using them and found it hard to keep the patch on and decided to purchase some nicotine oil from an essential oil vendor and commenced to use DMSO and nicotine oil on another areas not related to Dupuytren's Growth.
I replaced the DMSO only to a mixture of 3 DMSO : 1 Nicotine oil and commenced to rub it in the Dupuytren's Contracture occurring on the right hand.
I applied every 3-4 hrs, Nicotine has a 4 hr life in our body.
2 months later, now, the Dupuytren's Contracture occurring on the right hand is in full remission, my body is removing the growth, (can't feel it) and I can get my hand flat onto the surface when doing push ups, that feeling of the hand flat without the burning as the growth is stretched can only be appreciated by a Dupuytren's Contracture sufferer.
Warnings, very easy to overdose with nicotine, when you over dose you realise nicotine is not a party drug, not fun, not super dangerous, goes in 3-4 hours.
The mixture of 3:1 of DMSO:Nicotine, 4 drops will give an overdose though this disappears a lot as your tolerance builds up and on the hand harder to overdose. When I did it, it was on the back of my head.
Easy to fix, increase the amount of DMSO to 6:1 or 8:1 but I have not tried those ratios,
I'm using 3:1 and that appears to be able to reduce the Dupuytren's Contracture damage back to a non annoying stage in 3-4 months topically applying, I'm not sure what occurs at the end and I'll repost when that occurs, and please remember, this is not medical advice, just what I tried and what occurred

If you search the forum you can find a few questions and experiences of using DMSO usually with potassium iodide. Care needs to be taken as DMSO transfers whatever's on the skin through to the blood stream. In some cases of using it with SSKI there have been (anecdotal) reports of interference with thyroid function as a result. It most often comes up as a treatment for nail fungus when mixed with various agents, but with dubious results. I have not heard of using it with nicotine before or for DD, but presume there will be a risk of nicotine addiction or intolerance, and related side effects, just like with smoking or vaping nicotine. In any case there are almost no anecdotal reports of success using DMSO/SSKI with Dupuytrens. I personally would not try this but thanks for reporting it anyway.