Acanthosis Nigricans?

Okay I am a 21 year old male I am obese and I really up till about a month ago never really had "good" hygein.  Well I started noticing my neck was kind of light brown like it had just built up dirt and I have tried scrubbing it with many different body soaps and under my armpits I also noticed that they are kind of light brown.

I was considering this was most likely just dirt that embedded itself good in my neck and such but no matter how hard i scrub it doesnt want to come completely clean.  Then I started doing an online search on what I could use to clean my neck and I came across an article about Acanthosis Nigricans.

Now diabetes does run in the family somewhat as I believe about 2-3 of my relatives have/had diabetes.  This got me worrying alot because I am only 21 but I am obese.  And the thought of Diabetes just impacted me.

Now I know Acanthosis Nigricans can be treated since it is "pre-diabetes" and I have a doctors appointment in a few weeks and am going to get tested.  If I shape up and start eating better/get out more with Dr's advice would I be okay?

I have never liked being obese but for me it has always been hard to lose weight/stick to a diet but now that I learned about this I am seriously thinking about taking my life in another direction.

So I guess i want to ask is there really any other symptoms to Acanthosis Nigricans than browning skin around the neck and other places?