What do i do about my daughters ringworm?

she has had it for at least a month but i didnt know what is was til 2 weeks ago. so for the last 2 weeks we have been putting anti fungal cream on it. yesterday i had an OB/GYN apt and the dr asked what kind of cream i had been putting on it and i showed it to him and he said that it was the right kind but i had told him that it had been getting bigger, all he said was that it takes forever to get rid of. so my question is what do i do about it getting bigger. is it something i should worry about. my dr didnt say anything about it, to be honest i am not even sure he heard me say it was getting bigger. any comments would help. thanks