Brief Answer:
Please attach an image

Detailed Answer:

Hello,

In order for me to provide an informed opinion and in the absence of a physical examination, I would need to see a picture of the rash.

Also, please answer to the following questions: When did this discoloration first appear? Did it grow in size over time? Do you take any kind of medication? Also, please look carefully through your entire body and see if the discoloration is present elsewhere.

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Brief Answer:
Dark spots

Detailed Answer:

Hello,

Due to the fact that this discoloration has been present for a long time, without changes and does not appear elsewhere in the body (which would imply something more serious) in my opinion, is common dark spots that usually appear on the skin, neck and chest and are due to sun exposure. If this is a cosmetic issue for you, I recommend using lightening cream or a glycolic acid peel. I also recommend you use a high SPF sunscreen when out in the sun.

As for the lump under the jaw I do not think it is related to the discoloration. In most cases, an enlarged gland under the jaw is due to a viral or bacterial infection. However, I recommend you see a doctor to have it checked, in order to rule out a more serious cause.

I hope this helps. You are welcome to ask any further questions.
Take care

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