My cat's dog bite wound is infected and smells bad. What now?

Hi and thanks for using Petco Pet Education Center, formerly Petcoach! Sorry to hear about Mano. Sorry to hear about your other cat. Puncture wounds especially from bites push surface bacteria and oral pathogens from the biter deep into the skin and underlying area called the subcutaneous space. There the bacteria multiple and can travel along tissue planes. I would advise you taking Mano to your veterinarian and let them evaluate the significance of the bite. Your vet will advise a treatment course including antibiotics, possible surgery to place a drain, a rabies shot if deemed needed, medicine for pain, etc. The only thing you can do at home is to apply hydrogen peroxide making sure the eyes are covered and protected. Warm compresses on the area multiple times over the next few days. I'm not familiar with Cicatrin powder but it appears to be antimicrobial in nature. This powder will only treat the very surface of the wounds and may not get down into the deeper layers but I guess it's ok to continue using it. Only use hydrogen peroxide once to cleanse the wounds. If you can get some chlorhexidine solution, you could use that daily to clean the wounds. Good luck with Mano.