hahahahaha - sorry for laughing - don't light ANY matches in the room
if it's bothering him that much (if it were me) - I'd change food -
and on his itchy skin - have you tried oatmeal shampoo or any medicated shampoos for itchy skin ? Why are the bumps only on his head and neck ?? do you think something bit him or is he wearing clothes that are rubbing on his neck ??? Collar ? something he sleeps on maybe ?? There's so many things it could be - the detergent you use to wash his bedding etc
I would ask the vet about that because it's not normal for a yorkie to have a rash