the only way you can be protected is through prayer and reading holy Qur'an. it can be possible something was done. this type of disease can get serious but it also runs in families, did you know that? i have met many asian people with this type red sores on there body like on arms and stuf.
as far as i know for a person to be really seriously effected with a disease due to black magic. they would have to be not practicing the deen at all so the protection that you get from Allah is limited
''Most certainly, my servants you cannot exercise control over them except those who are deviant who follow you''(Al-Hijr;42) '' Most certainly he satan has no power over those who truly cherish faith and our trusting upon there lord; rather his power is limited only to those who take him as a protecter (besides god) and thus associate partners with him.''(an Nahl; 99-100
When your daughter was born you were afraid that she should not get any evil eye so you dressed her in less attractive clothes believing that this would mabe protect her.. this is where we go wrong in our faith, we believe other things will protect you besides god.. that is where people make the mistake. you need to trust upon your creator sister. that would not protect anybody of evil eyes. its only Allah that can protect us from evil.
recite this daily Al-fatihah
the last three chapters of the holy qur'an surahs 112,113,114
ayat al-kursi Al baqurah
blow them on water and yous should all drink including your daughter.. do it daily.
read the 4quls on a regular basis both in morning and evening three times or more