It is normal for the injection site to be swollen. It is not because of incorrect way of injection. Please do not worry for the same
Next Steps
Do not try and press the area too much. It is advisable to keep a watch. If you feel the lump is increasing in size or if pain or fever persist, schedule a visit to the doctor.
Health Tips
Applying the area with glycerine magnisum sulphate will relieve the swelling. Do reach me online if you want more info