Hello,
You have not mentioned your age but for such a patch, actinic
keratosis and basal cell carcinoma needs to be ruled out.
Actinic keratosis appears as rough, red bumps on the scalp, face, ears etc and may invade deeper in the skin to become a fully-developed squamous cell carcinoma. Hence this lesion can be a squamous cell carcinoma.
You need to get this examined and biopsied from a dermatologist to confirm the diagnosis.