that is typical teenage...you have nothing to worry about with her mental health. teenagers actually use a differnt part of their brain when they are assessing situations and facial expressions than adults use. therefore the communication barrier is pretty bad at this age it gets better with time though...just let her be herself......especially being a girl i understand the whole hair and self image thing. all girls are different some take it to a huge extent and others not so much. take care
Your daughter sounds like a typical teenager to me, and honestly your concerns sound a bit overblown. Sixteen is a very angsty and stressful time. It is normal for a 16 year old girl to obsess about hair, struggle in school, and even "forget" about a chemistry exam.
If you are really concerned, then I'd find a therapist who works with teenagers and families. If she is struggling in school then a tutor may be beneficial.
I remember from my own school days that it is important to get a tutor as early as possible before the grades get into big trouble. It is also important not to overly-stress about these things. A missed chemistry exam may be troublesome but it will not ruin her life.