This entry is for the tree, the next is for the fungus.

Actually I made a pretty big mistake here, In the first picture there are actually two different shrubs of different species which I assumed to be all one individual. The fungus has not infected the oak, it has infected the nearly identical Lyonia ferruginea growing beside it, distinguished by the flowers and the Exobasidium infection; I will make it a new entry. I have rearranged the photos so that the first 3 are of this species and the latter 3 are of the misidentified species.

Entry for the actual host of the fungus, Lyonia ferruginea: https://www.inaturalist.org/observations/210618982