knot on puppy's belly, looks like bite
My puppy had a tiny place on his belly when I got him 5 weeks ago. It looked like an ant bite then.
Today I noticed is about 1/2 inch around and is red looking on the edges.
If you've had your pup for several weeks and this lump/knot/pimple is still there and getting bigger, or more irritated, then it needs to be evaluated by your veterinarian.
It could be an insect bite that has become infected (the reddening suggests infection or irritation), and may need antibiotics.
If it had been a few days, I'd say you could afford to 'wait and see' for another couple of days, but after 5 weeks it needs to be looked at asap.
Best of luck with your puppy, hope this clears up soon.