You have allergies, and your doctor thinks allergy immunotherapy, or allergy shots, might help you feel better. The goal of allergy shots is to improve your allergy symptoms. But, there can be side effects. Those side effects are around the injection site, like pain, itching, bleeding, or swelling.
A formal sanction is a reward or punishment given by a formal organization or regulatory agency, such as a school or government. An informal sanction is a spontaneous expression of approval or disapproval given by an individual or a group, such as a standing ovation or gossip.
The formal register is more appropriate for professional writing and letters to a boss or a stranger. The informal register (also called casual or intimate) is conversational and appropriate when writing to friends and people you know very well. The neutral register is non-emotional and sticks to facts.