I agree with DROCK.... it would be different if you had 5 pages to write all of this out and make a CLEAR point... but you don't!
You need to make effective use of the space you are alloted--which is not that much--and WOW the person reading it. It has to have a purpose, and you need time to make that purpose shine.
Also, it seems as though writing your PS with that topic really limits how much space you have left to discuss other aspects of yourself. To go on and say that hey I didn't like the dentist but now I do and I realize how important it is is sortof a waste of space. Anecdotes are only useful if they illicit emotion from the reader, and yours just sounds like any kid who used to dread the dentist (NO OFFENSE). It would be a much more effective use of space if you simply stated (like DROCK mentioned) that you realize the importance of a doctor-patient relationship.
You can find other things to talk about, I'm sure. GOod luck!