You are having a reaction to your immunization. Reactions can show up as:
Tenderness or a red area at the injection site.
Tiredness may develop over the first 2 to 3 days after your shot. Severe reactions are very rare. Only take over-the-counter or prescription medicines for pain, discomfort, or fever as directed by your caregiver.
The DPT shot (diphtheria, tetanus, pertussis) may leave a painless lump at the injection site for several months. The MMR (measles, mumps, rubella) and VAR (chickenpox) vaccines can sometimes cause a fever, rash, or joint pain and swelling 2 weeks after the shot. Get plenty of rest and take your medicines as prescribed. See your doctor if your symptoms get worse, or if you are not better within 3 days.