I would be afraid of a medication being poisoness, I would just stick with vasiline, unless it gets worse, then I'd call the vet.
Sometimes when anal glands are excreted alot of dogs will scoot around and act as if they are really itchy.Unless the anal glands are infected are abcessed it should pass within a few days.Also if thay shaved around the rectum it could possibly be clipper burns.You could use Neosporin or a Hydrocortisone cream or spray for a few days.If you feel it is more than just irritated i would probably go ahead and call your vet and ask them what they think and what you could do.Good Luck.I hope he gets feeling better soon.
Vaseline isn't the best bet for this area. It's not water soluble and can trap bacteria underneath it.
Expressing impacted anal glands is kind of like popping a zit. It's going to be irritated for a few days, and of course, the dog is going to lick any irritated area. I've found Dermachlor Flush Plus (available from the vet) to be a great antiseptic and antifungal rinse that also prevents most dogs from licking an injury.
Dermachlor is great to have around the house for any minor injuries your dog picks up and also for treating "doggie athlete's foot". If your dog gets smelly feet in spite of a thorough wash, there's fungus present - usually yeast.
If your dog is still licking and scooting after 3 or 4 days, have your vet check for an anal abscess. Some dogs need their glands expressed very frequently, and if they aren't an abscess can develop either visible from the outside or just inside the rectum. In that case, your dog will need some antibiotics.