I also pick (and bite) the skin around my nails. Fidget toys have been hit or miss for me. Two big problems have been not having them on me regularly and being noisy enough to annoy others (particularly my wife).

What’s really worked for me are cheap silicone rings. They’re stretchy and quietly keep my fingers busy. And I can literally wear them to have them available at any time.

Pharmaceutical grade speed, not meth. Though methamphetamine is actually also a schedule 2 drug and can (theoretically) be prescribed by a doctor.