If a mole is scratched off, it typically grows back to the original structure and formation, according to WebMD. Moles that are tender, oozing, scaly, swollen, itching and red should be evaluated by a dermatologist to screen for types of skin cancer.
When a mole is scratched off and appears infected or changed from its original formation, physicians often remove a tissue sample from the mole for a biopsy to determine if it is cancerous, according to WebMD. During the biopsy, the entire mole and the rim of skin around it is removed before the wound is stitched closed.
A mole that does not change shape, grow or change in pigment color is often harmless and should not be scratched or removed, according to WebMD. People should have moles evaluated if one half of the mole does not match the other half, if the color is not consistent and has changing shades of tan, blue, white, black or red and if the diameter of the mole is larger than a pencil's eraser. In addition, if the border of the mole is irregular, blurred or ragged, the mole should be examined by a physician.
Moles can be removed for cosmetic reasons even if they are painless and do not change in formation or color.