You can't change the physical body with Magickal means more drastic than moving small amounts of cells (like helping to release blocked arteries using biokinesis, which is very, very complicated).
That being said, spells created by the caster actually work for the caster better than others, often times. Another thing to note is that the rule of three is not entirely a universal law (that's not to say that someone won't try to wish negativity on you for casting ill upon them).
All in all, I'm saying to be careful. I cannot stress this enough.