If you'd rather start a treatment based on a working diagnosis, then your vet will most likely make a presumptive diagnosis of a deep pyoderma secondary to a tick bite. (petsmagazine.com.sg)
The Peke's deep nose wrinkle can also develop skin fold pyoderma. (soonervet.net)
Localized demodectic lesions may benefit from topical antimicrobial agents such as mupirocin, benzoyl peroxide, chlorhexidine, or ethyl lactate when secondary pyoderma is present. (2ndchance.info)