I'm developing a teacher review Android Application.

By now, I intend to create ~900 tables, each representing a professor. Each table entry may have a area for user comments around the teacher. Every time a user adds a comment, a brand new entry is added under that professor

Is may well approach to take relating to this? I seem like there might be a far more efficient method of carrying this out. Also, will getting 900 tables be too much for MySQLite?

I had been also considering getting 1 table which will contain all of the professors, and also have the user comments like a area. Then, when every new comment is added I'd in some way add 1 extra area. I do not think this uses databases correctly, but is it feasible (to +1 the amount of fields)

You don't want 900 tables, you most likely have to have one Teacher table with 900 records. You might want to educate yourself on some database design principles and also the Relational Model. Probably the most useful area of the links might be the good examples within the Relational Model.

I would suggest that you simply read a couple of articles on database design fundamentals.

This is a very good one which should enable you to get began on course:

Fundamentals of Relational Database Design

Without starting it to deep you'll need a minumum of one table for those professors, one table for those customers and something table for that comments.

create table tbl_professor (id integer primary key, name text, ...)
create table tbl_user (id integer primary key, name text, ...)
create table tbl_comment (user_id integer, professor_id integer, thecomment text, ...)