Welcome to HCM.
It is most likely infected pimple.
Take proper local care,wash your face with anti septic soap.
You can apply clindamycin
gel.Start complete course of oral antibiotic like amoxy/clavulinic 625 nd nsaid
to subside pain and infalmmation.
Pain in throat and right arm is due to infective drainage
in the lymph
It will subside with this treatment.
Consult your physician for further guidance and medical management.