Theoretically the mains are supposed to run on a thin coat of oil and not make metal to metal contact (mostly). Scoring is an indication this isn't the case. Excessive heat (from friction) can destroy them quick. Blue/black spots on the steel is an indication things have gotten seriously hot, straw colored patches usually means moderately hot. The main bearings are usually layered and when the top layer is worn through (usually in spots), this can also be an indicator your clearances may be to large.
Most times your oil pressure will start to drop as the clearance in the mains and connecting rod bearings grows.
I've seen a lot worse than what you have. Most times I buy some plasti gauge and check the clearance. Plasti gauge is cheap, the only downside is whatever you are using plasti gauge on has to be oil free, oil melts plasti gauge. The plasti gauge will also show (highlight) the high and low spots on your bearings.
I find me a nice flat working area and use small wooden blocks around 3/4" thick, 2-3 inches wide and 4-6 inches tall and a hammer to straighten the pan back up. Just using a hammer takes more skill than I have. A nice flat piece of plywood works well as a base to hammer on, especially old plywood that has gotten really hard.