How Can I Tell if my Breast Tissue is Torn?

I would say you didnt tear anything as it is unlikely, specially since the implant is placed in front of the muscle.
The indent you see may possibly be the implant ripple as you are in front of the muscle and dont have the muscle covering the implant.

This is a difficult question to answer. Breast tissue generally does not tear. However the muscle can. Given the above muscle location of your implants, this would be highly unlikely.
There are numerous potential imaging techniques you could potentially use to make a diagnosis. However, this could be quite costly and in the end the question will be if you would treat or correct the problem.
If your condition remains stable, I would not pursue and additional intervention until such time that you need a revision.
You may want to obtain a second opinion.

The feeling you had may have just been normal post-op discomfort that can feel like searing or tearing pain. If you are unhappy with dents or irregularities of your implants, you should talk to your doctor about adjusting the implants.