Wounds would accumulate over time to your Heal/Action (Stamina)/Mind (Mana) bars. Example...
Before fighting 4-5 mobs or players:
Health - 1200
Action - 900
Mind - 600
After fighting 4-5 mobs or players and regening your HAM bar (assuming you took damage) -
Health - 1197 / 1200
Action - 898 / 900
Mind - 598 / 600
In order to get your HAM back to optimal function you'd need to be, or have, a Medic or Doctor heal your wounds. Campfires would heal your wounds at a much slower pace.
Battle Fatigue... BF accumulates over time during combat. If you fought one mob or person it may raise by a few depending on the length of combat. If you fought 20 mobs or players, it might raise 10-20. It all depends on the circumstances. Battle Fatigue gradually lowers the effectiveness of your skills as it raises.
In order to heal BF you would have to watch or listen to an Entertainer (player profession).
Something like that in Xsyon would be alright with me. We already have campfires. Medical skills are going to in at some point. Some sort of Battle Fatigue could be healed by campfires, too.