i've broken my index knuckle twice by doing stupid things in the past... its now a good 1/3 larger than all the other knuckles and it took a good few weeks to stop hurting and being able to push on it.

bruising knuckles are nothing until you've bruised your big toe and all 4 little toes by rolling/stepping on them while barefoot That took alot of time to heal

my advice is to take care of your hands, its 'closing the door after the horse has bolted' i know but if you screw up your knuckles now, you will hinder your boxing future as they heal softer, not stronger. Wrap your hands and ensure your punching correctly

if you are seeing brusing and but no local area swelling then you just have soft tissue damage or a brusied bone, nothing major, it all heals within a few weeks.