depigmentation- it is procedure to remove pigment like melanin
gum depigmentation , i suppose its some discolored gum in your case.. no toothpaste can solve your problem.. but lasers can be used to get the pigments removed..
note- these pigmented areas may get corrected by itself.. as sometimes hormonal
changes causes increased pigmentation..
u can have biopsy
done of the lesion if it is troubling you..and get the lesion diagnosed by oral diagnosis specialist..
My advise will be maintain a healthy diet, good oral hygiene
.. dont worry about such small areas.. but if you notice any change in senses perception/pain in region consult specialist immediately..
do gum massages with astringents as they help in constriction of blood vessels and may correct the gum problem..