I need to ask few more questions before answering your query. Early consultations can prevent complications. Kindly contact me on whatsapp chat  (84960595 six five) Dr Faisal Zoheb MBBS , MD PAEDIATRICS , PGPN (BOSTON), FELLOWSHIP IN NEONATOLOGY ( Newborn and vaccination specialist )

How is child activity/Any history of vomiting/seizure

There is a large hematoma, child'd hemoglobin will drop, coagulation disorders needs to be ruled out.

Visit your pediatrician

Greetings growing, hardening bump after a head injury in an infant requires immediate medical evaluation to rule out serious issues like a skull fracture or an enlarging hematoma. Potential causes for such a bump include a cephalohematoma (a collection of blood under the scalp), a subgaleal hemorrhage, or a simple hematoma" that is calcifying as it heals. Seek emergency care immediately if the baby shows signs like unusual sleepiness, repeated vomiting, or any change in normal behavior.

Are there any vomiting ? Or food regurgitation ? Check the anterior fontenelle is there bulging or not ? Any history of seizures? Lethargy ? Irritability ? Please consult a Doctor ASAP

Hai Any vomiting episodes or seizure episodes or poor feeding Get a CT brain done for confirmation

Consult with Pediatrician physically for further evaluation and treatment

This looks like a scalp hematoma after fall. It can increase in size and become firm over few days, that is common. But since it is increasing day by day, better to get the baby examined once to rule out deeper injury. If baby is active, feeding well, no vomiting, no excessive sleepiness → reassuring. Still, I would advise one clinical check ± ultrasound for safety.

Visit physically to nearby pediatrician.

kindly visit the doctor once to rule out any major injury

This is looks very big lump Urgently take to hospital and do A CT scan to look for any bleeding or hematoma inside the brain