Hi ! Good morning. I am Dr Shareef answering your query. Even though confirmation needs a physical examination, from your history of the tender lump at an injection site, it could be the starting of an injection abscess. I would advise you to get it assessed soon by a general surgeon before it transforms itself into a full fledged abscess which might need an incision and drainage later. Till then you could give him an anti inflammatory along with a proton pump inhibitor drug for a symptomatic relief. I hope this information would help you in discussing with your family physician/treating doctor in further management of your problem. Please do not hesitate to ask in case of any further doubts. Thanks for choosing health care magic to clear doubts on your health problems. I wish you an early recovery. Dr Shareef.