<s>[INST] My 18 month old girl slipped on water she fell back on her back and bumped the back of her head. ( it was wooden floor) she cried straight away she seems normal but has a lump, it was nearly bed time so I kept her up 45 min. Will she be ok or should I be worried? [/INST] Hi, thanks for sharing your health concerns with Chat Doctor! If I were your treating Doctor for this case of head lump, I would come up with only one and only possibility that is a hematoma or collection of blood under skin and soft tissues due to trauma and breach of vessels... This is generally painful; so please apply some ice/cool compress and pressure on it so that it does not increase in size but never rub it; it could get infected! If she vomits or cries more please consult your local physician / surgeon for an assessment! Hope this answers your question. If you have additional questions or follow-up questions then please do not hesitate in writing to us. I will be happy to answer your questions. Wishing your child good health. </s>