Sounds to me like you have mealy bug ! It is not uncommon for pothos to get it ..
What I would do , if it is a movable
plant , take it to the sink or tub and gently wash all of the mealy off , you can use safer soap , ivory soap , But the important thing is to get all traces of mealy off the
plant ..
Keep an eye on it for sometime to be sure you got all of it ..
Also you might want to up end the pot and look at the soil and see if you have it there as well ,,
If you are not sqemish about using pesticides it will help matters more quickly ..
Also for
plants of this size meaning they are not tall , I would get some systemic to place in the soil . This will kick in , in about 28 days or so internally and kill any remaining mealy that goes to feed . Read direction very carefully and apply the proper amount .. Keep hands out of soil for at least 28 days . By then the systemic will bind with the soil and be safe ..
Hope this helps