What wrong wit my guinea pig HELP MAJOR TROUBLE?

ok so my guinea pig has been acting wierdly he has sum red sores behind his ears hes my fovorite gunea pig i hav 3 boys and therebigger dan him he alsohas 2 holes on top of the holes wer he breaths i dnt hav enof money to go to a vet will he survive is this normal is he sick can u guys just tell me wats rong wit him he has also been ching himself way 2 much i need hellp pleeez