Need help figuring out a red welt on the side of my Cockapoo

Okay, we're really worried about our 9 month old Cockapoo. On his right side a little bit under by his chest and belly is a large red welt that has little bumps all over it. It looks infected but we can't take him to a vet until Monday. It just appeared there one day and grew. It's about half an inch in diameter, and looks extreamly raw. We had to make a home-made cone to put on him because he would constantly lick it and scratch at it. Before he had broken it open and then it crusted up as if it was going to heal, but never did.

This isn't urgent, we would just like to have some kind of idea of what is going on with him before we take him to the vet.

Any ideas or help would be very appreciated. ^^ Thanks!

 

It's hard to say without seeing it. There are so many possibilities. But it does sound sort of like a hot spot. They often start with an insect bite, the dog chews at it, it gets infected, and voila! You have a hot spot.

Whatever it is, if you can clip the hair away from it, so it doesn't get matted over the welt, and keep it clean and dry. A dab of antibiotic ointment probably wouldn't hurt it, either.