The bump shown in the image is highly suggestive of a keratoacanthoma, a rapidly growing, dome-shaped skin lesion with a characteristic central keratin plug. However, keratoacanthoma can look very similar to squamous cell carcinoma (SCC), a type of skin cancer, so it cannot be safely diagnosed from a photograph alone.
A lesion that grows quickly over days or weeks, becomes firm, develops a central crust or hard plug, or appears as a new pink/red nodule deserves prompt examination by a dermatologist. A skin biopsy is often needed to determine exactly what it is.
It is especially important not to pick, squeeze, cut, burn, or attempt to remove the central plug at home. If it is a keratoacanthoma or SCC, proper treatment can usually be very effective when addressed early.
Until the clinic opens, keep the area clean and protected. If it begins bleeding heavily, becomes severely painful, develops spreading redness or pus, or she develops fever, seek urgent medical care.
Bottom line: the appearance is concerning for keratoacanthoma versus squamous cell carcinoma, not an ordinary pimple. She should arrange a dermatology evaluation and biopsy as soon as reasonably possible.
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