The only chemical/drugs in Soolantra (compared to a normal moisturizer) is ivermectin. In my case, quiting with Soolantra didn’t result in a worsening. Also note that if you aren’t using any moisturizer, than quiting with Soolantra isn’t just quitting with ivermectin, you then also quit with using a moisturizer, which can lead to dryer skin and thus increase the skin problem.
Soolantra is tested and designed for rosacea. Maybe they mention 4 months because they haven’t tested it for a longer period. If you want to minimize any long term risk while using it, you could also try to lower the amount per application or the frequency of application.
Btw, I did have scalp itch when I sweat a lot during exercise combined with a warm environment, which may be cholinergic urticaria. But I haven’t noticed it anymore since intermittent fasting.
I would recommend to at least use a moisturizer comparable to the one mentioned here: Skin hydration & Moisturizers and to give Sudocrem a try. And if you’re open for further experimentation, than you could try intermittent fasting (IF). (IF can also have a large positive impact on diabetes, but it can be recommened to discus this with your doctor if you’re on special medication for it.)