Should expired TCA peel be used or not?

it is not recommended to do ANY inflammatory acid peels at home let a lone this which is way too strong for anyone to do in a large area and UNSAFE.  try an at home peel with cosmelan or enlighten.  Best, Dr. Emer.

50% TCA is not used by ethical clinicians because above 35% TCA, trichloroacetic acid can cause unpredictable scaring that will permanently disfigure you. Yes you can buy the product online but that does not make it safe. In my opinion it is criminal to sell this product to the public. The Neostrata product you have is more likely to be glycolic acid. Still this is not a home use product. Those have a concentration of glycolic acid of 6 to 10%. A 50% glycolic acid is a professional product that also has the risk of permanently disfiguring. You are strongly advised not to use these product. Home chemical peeling is not a good idea. 

I wish to join the chorus. NO ONE should EVER do a TCA peel at home. There are 2 reasons for this. First, even experts have occasional problems with these peels. I have seen major problems with them done by experts. To even try one without the significant training and years of experience makes no sense at all. Secondly, any TCA, or other peel agent you get, have a very high probability off NOT being what they are supposed to be. It sounds like you used this before. If so, I can assure you that whatever you have was not 50% TCA. If so, you would be asking how to fix the scars. I have been doing peels for 40 years and have never used TCA over 20%.