Zippy13 is right.
What you want a gun to do - is recoil under your cheek bone. If you bruised your face ( and this is a common problem ) - its probably sore right where the meat in your face contacts that cheek bone.
If you put your hand up to your face / fingers flat toward the floor - and just in front of the cheek bone ... If you angle your hand - close to your cheek bone - you can probably feel the soreness - if you move it straight back. Now as you flatten out your hand next to your face - imagine the hand moving back and forth just under that cheek bone ( there is probably no pain ). So like Zippy said - that angle has changed.
You can see it on your guns - if you unload them - and lean them both up against a wall ( with the rib flat on the wall ) and look at the angle of the comb next to each other ..... Even a difference of 1/2" is a lot.
The best long term fix - and cheapest - is a stick on comb pad sold thru Brownells and others.
Here is a Brownells link for Scope EEZ - a product I've seen work on shotguns too - but they have others too.