This actually isn't too uncommon, it happens a lot. Normally, professors may ask you to write a rough draft that includes details about you personally, and then they later add comments themselves from their experience with you. I don't have personal experience with this, but know a number of people who did this themselves. It's a hassle to write a letter for yourself (and awkward), but if you don't have other options, then you might as well do it.
To answer your question, what most pharmacy schools most likely look for are personal qualities in a letter (determination, communication, etc etc). They want to hear what kind of person you are, not how well you did in a class (which they can see on your transcript). Hope this helps!