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seem like an infection as elderly are more prone to infection; most common organism being staphylococcus
I presume your mother is not diabetic.
You are doing the right job by applying antibiotic ointments
. However I would suggest you to cover the lesion with a sterile gauze (which is available over the counter) instead of band aid as there is a tendency to cause skin peeling especially over the fragile infected area in elderly.
It is absolutely essential to maintain proper aseptic conditions. Avoid unnecessary handling the affected region with bare fingers. Watch the progress. If there is not proper healing in the next few days or if your mother develops fever with chills, you would need to seek prompt medical help
. Oral antibiotics
may be needed in such cases.
In addition complete hemogram and blood sugar testing is entailed if there is worsening of the condition.
I wish your mother a good and speedy recovery.