I notice this post is a couple months old but... Absolutely! I am a ballet teacher and though I do not know the details of your previous pointe experience doubt they have ruined your ability to dance. Your teacher can work with what damage you may have done, if not physically, regarding your technique. Minus a serious ankle injury that might inhibit a career in ballet you should be fine assuming you follow your teacher's proper syllabis and do the exercises. As for what those exercises are... there are so many. Those your teacher does during class, and those that can be found in a basic ballet book available at most book stores. They may seem boring or mundane at first but it is these simple exercises - from fondu at the bar to passe in place - done thoughtfully and with proper technique that will do wonders for your dance and create that muscle memory that makes proper technique natural.