Please for the love of god don't start with anything higher than 12.5%. One bottle of the 12.5% will last you 4-5 peels. Spread them out about 2-3 weeks apart, no sooner.
Understand that it isn't an instant cure. You're putting acid on your face, so your skin has to regrow and all that. I didn't really notice results until my 3rd peel (of the 12.5).
In my opinion (been an acne sufferer for years, now just deal with scars and occasional blackheads), tca peels are a LONG TERM treatment. You dont just buy a bottle, put some on, and expect results. I plan on doing several peels over the next year. You have to think long term if you are looking for dramatic results. You can speed this up by going higher %, but youll have the flaking, peeling, horrible downtime that people talk about. I have a job so I can't hide for 3 days at a time. With 12.5, you dont get this, but it obviously takes more treatments to get the desired results.