Massive Haematoma on 4mth old baby head

okay im already feeling very guilty and i will never leave my child unattended ever again. I had my 4 mth old baby on the kitchen counter laying on a change pad. i was cooking dinner at the time and had my back facing her. She kicked herself off and landed on her head. I took her to the ER where she had a CT scan. It showed a massive Haematoma with no underlying fracture. Im glad there was no serious damage but she is left with a huge ugly lump on her head. This happened 5 days ago and the lump is still very large. My question is will this go away? Im worried the lump will stay permanently. Is there anything i can do to make it go down? she is only 4mths old so it would be hard to keep an ice pack on.