There are two main pests of apple that bore into the fruit, the apple maggot and coddling moth. With codling moth, the hole in the fruit will be filled with frass (insect poop), and when the apple is cut open, the tunnel will reach all the way to the core. Fresh holes in the fruit will appear in May/June and at harvest. With apple maggot, the hole will be free of frass. and the tunnels may turn brown with a bacterial rot. The fresh holes appear only at harvest. For a comparison of the two pests, refer to: https://s3.wp.wsu.edu/uploads/sites/2083/2015/03/Codling-moth-vs-Apple-Maggot-Homeowner.pdf. Based on your description and the appearance of the hole, I believe it is apple maggot. I don’t know if the brown splotch on the fruit is related to the tunneling of the apple maggot, it is hard to say without being able to inspect the damage to the fruit a bit closer. The best way to control both pests is to carefully monitor for them using traps so that you can time your pesticide applications. I suggest you contact the Washington County Master Gardener hotline (you can leave a voice message at<personal data hidden>). They should be able to take a closer look at the fruit to confirm the diagnosis (you can also send them photos of plant disease symptoms for assistance with diagnosis). They may also have information on timing of pesticide applications for codling moth and apple maggot in the north Willamette valley. The pesticide you sent a photo of is a dormant oil, it should be applied during the dormant or delayed dormant season. Dormant sprays are used to control soft bodied insects such as aphids or scale, it will not be effective against codling moth or apple maggot. For a schedule of sprays for apples, please review the OSU Extension publication on Managing Diseases and Insects in Home Orchards (free to view or download online).