He’s acting completely normal, it has grown considerably in the last couple of weeks, my entire family has been locked up due to everyone having covid so that’s why I’ve reached out on this site. He is a rescue and we don’t know how old the big guy is, we’ve had him for close to three years and we got him fully grown.
It's good that he's acting normally. I hope it isn't bothering him too much. If it's growing that quickly, it's probably (my untrained guess) an abscess rather than a tumor. This will likely need to be removed/drained by a vet and treated with antibiotics if the cause is determined to be a bacterial infection. Due to the location, I'd be concerned about an infection eventually spreading to the sinuses or eyes. It sounds like your situation limits access to a vet, but I would bring him in as soon as it's safe for you to do so. I hope you and your family recover quickly and fully!