My 7yr old daughter get bitten by a scorpian tow weeks ago now she has a big red hard ball and it is itchy. do you think is normal or is it bad ? will it go by it own ?

A firm swelling under the skin of a bite could be an organized blood clot(hematoma) from bleeding that occurred with the bite. Concerning signs would be spreading redness & burning sensation that could indicate a secondary bacterial skin infection(cellulitis). Try applying warm compresses to see if the hard ball softens &recedes. If not have an MD examine her &advise you.