dont fight. the damage you can do to yourself long-term is not worth it.
learn to refine the art of walking away, and being above petty sh1t, because that is something you need to keep doing throughout your life. When a situation develops, try and "zoom out" like with a photographic lense to observe yourself in time and space. A little tiff with 3 guys you dont really care about, a situation you will have forgotten in 2 years time, none of this is worth risking long-term bodily damage that may NEVER go away. A guy puts a finger in your eye socket, and you'll never see with that one again. A guy knocks you down and stomps on your head, permanent brain damage. A guy smashes a bottle across you're face, you'll wear that scar for decades.
I know it hurts you to back down but you have to realize we dont live in caveman times anymore and the people today at your age that are really good at fighting probably have nothing going for them. You have a lot more to lose than they do. Its always this way. The people who are good at fighting and who want to fight have nothing going for them except that.
Caveman times arent coming back, its the dorks and thinking types who rule the world now, for better or worse. The nations with the most macho cultures (for example Somalia) are easily manipulated and steered by countries with feminized cultures (United States) because of the advantages that accrue to cold-blooded examination of facts and strategic thinking which isnt a caveman or a tough's strong suit. Its better to be a thinking man than it is to be a fighting man. Thats all.