My 6 momth old rolled off my lap amd hit his head on our hard floor i was sitting on the floor to so it was a short distance 2 days ago he has no brusing no discoloration on his head just a mushy lump above where he had hit he hasnt had any signs of head trauma no vomiting eats and sleeps just fine even after it happend he plays and laughs like always ..very active ..if i touch the area he shows no sign of discomfort or pain should i be concerned ..