Yes, you can use the eye kind, it's basically the same thing.  Probably a good idea to pick up some of the spray when you can for the future, just to have on hand.  The comb is probably bruised and traumatized, not much you can do but let it heal and see what happens.  If it falls off eventually, it will be fine.  Chickens that get frostbite on their combs have it happen, it heals up and they just have a smaller comb.  And there is dried blood, and it will look black.  It will eventually dry up and flake off.  I would just try to make sure the injury itself is as clean as you can get it without causing more pain or injury.  Why veterycin is good, you can spray it on and leave it.  I would separate the cockerel for a while, if you intend to keep him.  They can be really rough while their hormones are raging.  It's entirely possible that he caused that injury or contributed to it.  They often grab the back of head or right behind the comb with their beak to hang on while mounting.  Young ones haven't learned manners or technique yet.  Some never do.