I'll take a couple of naproxen sodium and drink good coffee when fingers are a bit stiff...
If it is cool weather, snag some of the cheap chemical & air pocket warmer packets from WalFart.... When it turns hot weather, Wally usually dumps em, so you can stock up cheap... Feels pretty good holding in your hand to warm fingers up....
I am also a percussionist (degreed). I would sometimes run warm water over my hands for a couple of minutes before a performance.... Not good to get fingertips wet before playing a string instrument but you could stick a couple of blue gloves in your pocket to keep em dry...
Another trick I use for tendon pain in my left forearm near wrist might help. I tried it one day just for the pure hell of it. I had some odd boot hunting socks as we will use those for rice socks (fill halfway or so with dry uncooked rice, tie a knot, nuke for a minute or two, instant heat pad).... Anyway, I took a thick hunting boot sock, cut the foot off and slipped the rest covering my forearm with the cuff down at my wrist... Works great. A bit of pressure and keeps my forearm warm... Damn sure helps...