This question joins two things that should be kept apart, and the most useful thing this page can do is separate them again.
On the peroxide. With an open surgical wound, do not use skin cleansers, alcohol, peroxide, iodine, or soap with antibacterial chemicals. These can damage the wound tissue and slow healing. With pressure sores, do not use hydrogen peroxide or iodine cleansers unless directed by your provider, as they can damage the skin. There’s no exception for a wound that looks infected. Suspected infection is not a reason to reach for it.
On the infection. Signs of infection are a reason to contact someone, not a reason to step up treatment at home. Contact your provider for redness, increased warmth, or swelling around the wound; more drainage than before, or drainage that is yellowish or cloudy; bleeding; odor; fever or chills; increased pain. Contact your provider right away for redness, increased pain, or yellow or green pus, or excessive clear fluid around the injury. These are signs of infection.
Put together, peroxide is not the answer for a wound that looks infected, and an infected-looking wound is not something to treat yourself at all.
There’s a second reason this matters beyond the peroxide. When a wound is cleaned more aggressively at home, the change is being handled privately instead of reported, and reporting it is the active step. Infection can make a wound larger and take longer to heal.
If a dressing routine was given to you, keep to it while you wait to be seen, unless you have been told otherwise.