How long does a lump after dog vaccination take to heal?

The lump that appears after a dog is vaccinated usually disappears in about 2 days, and quickly within 30 minutes. A post-vaccination lump is normal because vaccination is a subcutaneous injection; sometimes the drug is not immediately absorbed and forms a lump. The owner need not worry, as it usually is absorbed and disappears in about 2 to 3 days.

To make the lump disappear faster, the owner can apply a warm compress to the dog.