There are three main categories of lesions two of which the salon professional need to be able to recognize. these two categories are?

There are three main categories of lesions, two of which the salon professional needs to be able to organize those two categories are skin diseases and disorder.  

Explanation:

The salon professional should be well expert in his field so that he could treat his customer very well. You should be aware of all the diseases and all the disorder related to the skin. He should be also expert in treatment for all those disease and disorder.

Also he must take proper certification from the organization. The certification is the genuine proof for the people that he is expert in the salon field.