There's some bad fuckers about. Sorry to hear about this, definitely notify the cops, that's a very serious injury, life impacting.
I was jumped by two lads before, got busted face and broken nose. I had no witnesses but put a complaint into the police the next day (they knew I was not lying by my face). They charged both, they had to pay compensation to me, and I also received compensation for the nose damage from the government injury dept, about £1000 in all.
Small injury but I had to go through surgery last year (after 10 years of crap breathing) on the nose (rebroken and scar tissue removed), as I was unable to breathe through it at all due to the damage.
I hope the damage is not permanent dude, get well soon.