Building the first heating massager for TMJ

I’m a Mechanical Engineer. And when I got TMJ Disorder and couldn’t find any products out there that would help me heat and massage my jaw muscles (as suggested by the doctor), I decided I might as well make one myself.
On the way, I’m learning how to design PCBs, integrating it with general product design, dealing with the FDA, branding, and so much more. It’s insane how much goes into making a product vs a prototype.
I’ve been uploading build logs if you’re interested