Hello. Thanks for asking from HCM.
I can understand your concern. The lump on your forehead even after 1 month post
head injury, might be due to some chronic pathology. Mostly it happens because of calcification of
hematoma or infected hematoma. I will explain both conditions to you and you can relate your symptoms.
Calcified hematoma is stone like hard calcification around blood collected beneath scalp skin. It feels as hard swelling, may be tender but usually without change in skin colour. It sometime needs surgical excision of hematoma wall and blood evacuation.
Infected hematoma is infection in collected blood beneath scalp skin. It feels as tender swelling, redness of skin and sometimes fever. It is treated by antibiotic course like co-amoxyclav therapy and surgical evacuation.
You can relate your features. Most likely in your case, it can be due to infected hematoma. You can apply cold compresses, avoid any further injury at same site,
consult doctor for evaluation. You might be advised
CT scan of head to rule out collection,
fracture at injury site.
Thanks. Hope it will help you. Take care.