In reply to Ramblin dave:
Some good advice above.
For me, finger tweaks have nearly always been caused by hard (for me) route onsighting or redpointing indoors.
I find that indoor bouldering I warm up more effectively, and am more relaxed about letting go if a hold doesn't feel right.
On indoor routes I just seem to get tweaks. I can't identify the precise instances as I've never had a sudden 'pop', just lots of tweaks that will start to twinge at the end of a session (and then persist for months). I think maybe it comes from being less relaxed on a hard route, or holding poor holds for longer/less dynamically eg. clipping.
My solution indoors is to use easier routes without tweaky holds for lapping/endurance work, and then boulder for strength and power.
For me, this has worked this year, and helped me improve 2 sport and boulder grades.
I've never hurt my finger tendons on a route or boulder outside.