Stuff that Reverts:
- Your weight distribution does slowly go back to pre-T areas. Yes, this includes your face shape, assuming you started T as an adult after your bones have fused. 
- You'll lose muscle mass, assuming your workout routine remains the same.
- Your skin and hair will return to their initial texture.
- The body hair and facial hair you've already gained will stay put, but it tends to get softer and lighter. 
- Your period will return, if you haven't had the relevant parts removed. 
- Your various bodily odors will go back to what they were pre-T.
Stuff that's Permanent:
- Voice change. If you stop while your voice is still breaking, it will remain broken. 
- Body and facial hair you've already developed (though again, the texture will probably change)
- Hair loss on the scalp 
- Genital Growth