We got 2 7 week old guinea pigs about a week and a half ago we had them out about 3 days ago and saw what looked like running lice on them (little white worm looking things) so we treated them with invectmine spot on and checked again today and saw no white worms but we saw black tiny dots in tbe fur not on the skin they are so small i cant see if they are moving does any one know what they might be?