An infection is caused by pathogens such as bacteria, viruses or fungi. It may occur after surgery or an injection, but is not necessarily related to a procedure. Inflammation without a pathogen is different and should not be called an infection on that basis alone.
Possible signs include increasing redness, warmth, pain, swelling, discharge or fever. Symptoms are not the same in every infection. Early medical assessment helps establish the cause and the treatment needed.
Depending on the findings, wound care, medication or another procedure may be needed. Rapid deterioration, feeling severely unwell or circulatory problems require urgent medical help. Even a small puncture site does not rule out a serious infection.