Seeing as how the Wiccan belief is to harm none, the spell that you cast is not specifically Wiccan of it intended harm on your mother. Also know that it is pretty unlikely that you caused her sickness on your own, your magick may have aided it in happening but the way I see spells is putting energy towards strengthening an outcome that already has a chance of happening. Also I personally do not believe that you can just 'take back' a spell like this although that is just my opinion. Maybe direct some healing energy toward her, but it is impolite to cast a spell on someone that does not agree with Magick or witchcraft so I would not do a spell.
About her not wanting you to go to a ritual. It is understandable that she may be skeptical about Wicca because of the misconceptions surrounding it. Explain to her that it is not about devil worship or any scary things like that. Tell her the similarities between Wicca and the religion that she follows, plus the basic beliefs such as a reverence for nature. All in all though, she is your guardian. If you are not of the age of consent then she can decide what religious ceremonies you attend. Until then, study your beliefs. And if you must practice them, be respectful and keep them on the down low. You can have your own version of the great rite, and heck, invite your boyfriend.
First of all, Wicca is a religion not a magical practice, so there is no such thing as a "Wiccan spell". And it would go against Wiccan ethics to purposely cast a spell to hurt a person. So I am not at all sure that you truly understand much about Wicca. However, if you're interested I'd be happy to give you some suggestions on readings to learn about what Wicca really is.
Secondly, do you understand what the Great Rite is? If you are not legally an adult and you attend such a ritual then all of those who are of legal age could be arrested and put in jail for letting you attend.
If your Mom is ill she needs to see a doctor. It isn't likely that her being sick is the result of the spell that you did. However, you might try doing a healing spell for her just in case.
luckily I can do the great rite, because my dad is a lawyer and there's freedom of religion and stuff. did you know that we, as wiccans, can sue people for not letting us do the great rite? they allow animal sacrifice in the united states, so I think I can do the great rite... now that I think of it, they let kids drink wine at communions and bar mitzvahs, so maybe they're just prejudiced. you don't have to listen to our oppressors. we don't want to let them win. my fellow wiccan did it in her car, her parents didn't get mad.
I doubt your mother's sickness has anything to do with your spell. And as Lark said, Wiccans "do no harm", so it was not a Wiccan spell.
As for the Great Rite, you must understand what the Great Rite is, which obviously you don't (from other posts). You are searching for permission to have sex, and trying to use Wicca as your reason for doing so. Not cool, little one, not cool at all.
I responded to your question about the Great Rite in your thread on this topic.
No, you can't sue someone for not letting you attend a ritual in which the Great Rite is performed. In the Unitied States, if you are under the age to be a legal adult then your parents have the right to determine your religious upbringing. If they do not approve of your following Wicca or taking part in the Great Rite then they have every legal right under the law to forbid or prevent you from doing so. This has been proved time and time again in courts in this country, as I'm sure that your Dad could explain to you.
Besides, as I said before, you aren't trying to go somewhere for the Great Rite, you are trying to go somewhere to have sex with one or more people. What they are proposing and what you are interested has absolutely nothing whatsoever to do with the Great Rite. You may be fooling yourself, but obviously you're not fooling your parents.
There is no such thing as an 'evil Wiccan spell' you know. For one thing the Rede clearly states 'harm to none' therefore even if spells were categorized by religious affiliation, there are no 'evil Wiccan spells'. Second, spells are not good or bad, it's your intent. You got mad and you cast to harm [harm does not mean kill in this situation, it means hurt. You wanted revenge because you were upset therefore karmic retribution] Ignore going to the Great Rite [which according to your other post it's not] with your boyfriend and focus instead in rule one of Wicca. If you aren't mature enough to grasp the Rede, you are not mature enough for the Rite. If you are serious about being a Wiccan, start with defining 'harm' because making someone even a little sick on purpose goes against it.
