Does hair revert back after having a relaxer?

My hair is slightly nappy, very thick and curly. (I'm multi-racial so it is 70% Black texture, 30% White. And its not as ethincally nappy as real Black hair, but its nappy enough that if you try to run a comb through it when its dry, the comb will break....Believe me it has happened.) I put in a relaxer (It was a relaxer for White hair, as my parents were afraid my hair isn't coarse enough for a real one.) It didn't straighten it, just made it less curly. Three months later, a touch up was applied to the roots. So it's been about 7 months now and my hair is in that state still. My new growth is not as curly, just nappy. My mother ranted on about how we permanently changed my hair, and it will come back even nappier than before. Please, shine some light on this situation! Is that true? Does hair revert back to it's natural state after some time? Or do we have to wait for the new growth to come in? Is there any way to 'undo' or fix a relaxer, or something like that? All answers are appreciated :) Please and thank you.