Best General Surgeons in Bengaluru

Pain and swelling after a misplaced injection are common, similar to how your knee swells after an injury. The needle may have injured a nerve or tissue, causing the discomfort. You can apply a cold pack to reduce swelling and take a painkiller for relief. If the pain and swelling persist or worsen, see a doctor. 

The risk of HIV or Hepatitis B infection from the scenario you told me about is extremely low. HIV and Hepatitis B are primarily transmitted through the infection of the blood of the infected persons. The symptoms may include being feeble, jaundice, or flu-like symptoms.