His face was blasted open ... his eyes were swollen shut ... but MMA fighter Mike Barreras still posed for a photo after getting destroyed in a Bellator fight -- and the pic is NASTY!!!!

Barreras' ass-whooping came at the hands of Bubba Jenkins -- who put a hurting on Mike during an undercard fight at "Bellator 97," which aired on Spike TV.

The loss knocked Barreras' record down to 5-6 ... which hurts ... but not as bad as his face.