Whats wrong with my guinea pig?):?

I just got her from petco 3 days ago, today my friend noticed that izzy, my guinea pig is sneezing and has crusties on her nose and in her ears. Shes sneezed a little since ive got her. Should i take her up to petco and ask them to have her see.the vet because they said they would send her to the vet if somethings wrong with her... what do you think is wrong with her