Sorry, safron, but triple antibiotic ointment IS neosporin! It is the brand name for bacitracin-neomycin-polymyxin - read your label. And it is perfectly safe for, and often prescribed for, cats. The only danger is from anaphylactic shock due to allergy, which can occur anytime a drug derived from molds is used, even in people.
However, judging from your description of the wound, it sounds like it may be a burst abcess, and as such will need something less dilute than an over-the-counter topical antibiotic. He really should be taken to the vet, since these things, even after they burst, can get nasty really quickly.