Hello there. Thank you for your question and i appreciate your concern for your child.
As a previous Maxillo Facial surgeon i am accustomed to seeing children with knocks to their face, head and neck as well as trauma to the oral cavity.
The question is whether your child has suffered head trauma
which requires observation in hospital by medical staff. The first thing to note is that the safest thing to do is to take your child to the nearest accident and emergency unit
and get him checked over. The doctors will check his pupils and his responses, they will check the wound and check his symptoms.
If your child did not lose consciousness after the fall then you shouldnt be too worried, but it might be worth getting your child checked out regardless. The growing "bump" on the head sounds like a heamatoma, which is just a bleed under the skin which is encapsulated and causes a raised, red, sore lesion which will often grow until the bleed stops. With time the clot will break down the the bump will go down. Providing there is no pain, application of cold
compress and massage
can help break up the clot.
The other thing to not is if there is perfuse bleeding. If there is bleeding which isnt stopping, it is again worth taking him to the hospital .
Please dont hesitate to get in touch with further questions.
But without a full examination, my best advice is not to panic but to take him to get checked over as a precautionary measure.
I wish you and your child well.