
Hi We have the same breed...have you looked at his food?
Our first black male had similar treatment for itchiness & it didnt really clear completely.
Then at a show I discovered a few Pugs especially black were allergic to a well known good brand of food, (not supermarket brand/stock)
I then changed and it stopped within a day... his offspring was exactly the same I later found out.
Maybe it could be the weather/pollen issues if has it just started? They are low to the ground for grass and pestisides being put on & around it & I know of many also that seem to get this at start of summerand priton does ease.
Also Pugs do seem to have a few days where they seem to scratch as if it becomes like a habit they cant seem to stop, mine do have anyway and so has my friends & families but not that prolonged for the need of Vet treatment.
Hugs to your little one, hope its resolved soon nothing worse than a irritating itch!