The hyperpigmentation around your nose and mouth could be due to a variety of reasons such as acanthosis nigricans, pigmentary demarcation lines , seborrhoeic dermatitis and
vitamin B12 deficiency. It needs a video consultation to look into the type of pigmentation.
The colour difference from your face and body could be merely due to photomelanosis or tan because of sun exposure. It needs further assessment through a video consult.