Retired organic chemist and beer brewer so sterilization and sanitation are up my alley!
Specifically for your question, if it was me, I'd discard the wetsuit, buy a new one, then practice a vigorous sanitation routine for the wetsuit. While we like to think equipment can last forever, porous or scratched materials are notoriously difficult to sanitize. I hate to discarding any equipment but sometimes it's just time.
I've been brewing beer for 35 years so the topic of sterilization v. sanitation comes up frequently(and is applicable to scuba). Here's my brief explanation. Sterilization and sanitation are very different. Sterilization is pretty much unattainable in a home setting. It's a process that generally uses high heat and/or some pretty nasty gases that eliminate bacterial and viral entities(i.e nasty stuff) and also requires some very specialized equipment. Sanitation significantly reduces the amount of "nasty stuff" but never eliminates all of it. There are all sorts of sanitation methods: high heat, strong oxidizers (peroxides and hypochlorites), QACs, iodines, phosphoric acid, and alcohols(methanol, ethanol, isopropanol). In my opinion, household bleach(sodium hypochlorite) is a great, cost-effective sanitizer to use at home. Follow the manufacturers guidelines on using it and always remember to protect yourself when using it (gloves, eyewear, apron(as I have ruined many really cool t-shirts with bleach spots!).
Hope this is helpful information!
