The ankle is where both main kinds of leg wound turn up. Most venous ulcers occur on the leg, above the ankle. Ischemic ulcers — wounds from poor blood flow — can appear on the ankles too. Which kind you have changes the treatment, and it changes what the skin around the wound is expected to look like.
For a venous ulcer, the signs of infection are: redness, increased warmth, or swelling around the wound; more drainage than before or drainage that is yellowish or cloudy; bleeding; odor; fever or chills; and increased pain. Two signs are tied directly to infection: if the sore becomes infected, it may have a bad odor and pus may drain from the wound.
There is a complication at this site that applies nowhere else on the leg. You will wear a compression stocking or bandages over the dressing. Skin under a bandage is skin nobody is looking at. The treatment that helps a venous ulcer heal is also what keeps it out of sight between changes. So the check has to happen when the bandage comes off, on purpose, rather than being left for the next appointment.
And if the ankle wound is arterial rather than venous, the bandage is the wrong thing entirely. Do not wear compression stockings or wraps unless told to by your provider. These may restrict blood flow. An ankle wound that is getting worse under compression is a reason to ask which kind it is, not to pull the bandage tighter.
One more thing about reading the skin here. With a venous ulcer, the surrounding skin may be shiny, tight, warm, or hot, and discolored. On a leg like that, warmth and discoloration are not news in themselves. Change is. Check your feet and legs every day: the tops and bottoms, ankles, and heels. Look for cracks and changes in skin color.