I agree with the other posters, he feels different, itchy possibly a little sore pretty much like bad paper cut, not exactly pain but different. Nerves were cut during the incision so skin shouldn’t be all that irritated, either the dissolving stitches or glue may be wearing off causing the chewing or itching reaction.
The neuter site should be healed by now, I suspect its secondary irritation caused by the licking, put dogs cone collar back on and check with that the vet to see what they say. They may say keep the collar on another x amount of time or just watch to make sure he doesn’t keep licking or chewing. Our collie kept licking especially at night so we made him sleep with his collar on, was free from it during the day when I could watch him.
Try and keep the dog from licking until after you see the vet, don’t put anything on the site to help it stop bleeding or any antibiotic. Unless it’s dripping blood leave it alone, if he is dripping all over call the vet to let them know, otherwise if it’s just raw and red, may be oozing a bit let the vet do the proper treatment and check the surgical site to make sure everything’s healed up proper (they usually are healed up greatly now)
Good luck, keep your boy quiet and on leash for potty breaks until after the vet just in case so he doesn’t get irritated more.