hi im dr satya
welcome to health care magic,
bites by insects, reptiles, or bees, do have a similar picture.
since there is a single bite mark the possibility of snake bite
may be less, centipedes and similar creeping insects do cause a long streak like marks, scorpion bites are very painful instantly, bee or wasp stings have their stings in the middle, since your bite has black colour it seems that it has been due to some insect with a local toxin. the best treatment is to get a proper evaluation of the site and appropriate antitoxin given, make sure that it not toxic so that there is no harm to your limb or life. do visit your nearest hospital emergency and get the treatment done.