ok ... #1 remove the might prtector disc as soon as possible and totally wash out his entire cage and all toys.
that disc is highly toxic to the birds, it should not even be sold.
and the fact that the product is on the outside means he has probally consumed some.
i do not want you to panic or feel bad, you saw it on the shelf and assumed it was safe, these damned companies dont care about animals only money.
i myself had one at first until i was informed here on the forum of its danger.
get him to a certified avian vet as soon as possible and inform them of the cere issues(which is probally unrelated) and tell them of the mite disc.
do not use any type of mite repellant or mite shampoo or spray or conditioner without askig the vet, most of them are toxic on some level.