Why there is a dog knot under the skin of my dog after being spayed?

Its normal to be worried about the knot or bump under the skin of your dog especially if You have never felt it before.

Its highly unlikely that the spraying caused the knot, It may have been there in the first place and You just noticed it after the spraying. If however, You are sure that it wasn't there before the spraying, then it's very possible that your dog was hurt and injured during the spraying.

After some time, the knot or bump obviously got infected resulting to the pus.The Neosporin that was recommended was meant to avoid infection, but the infection was already there, and that's what led to the pus in the first place. What he should have prescribed was something to clear the infection. It would be a good idea to consult the Vet again. The pus will clear after the infection has been properly treated.

If however, the pus does not clear away with time, then the bump should be thoroughly investigated to rule out cancer. No need to panic though, most dog bumps also known as tumours turn out to be harmless.

Harmless tumours are very common. Most are usually a harmless mass of fat or fluid-filled swelling.They are normally removed through a minor surgery.