There are many different insects that could cause this symptom on your apples and trying to figure it out solely based on pictures will be challenging. I can give you some options and then if you do some more investigating, perhaps you will be able to figure out the cause on your own. One of the most common insect pests in Michigan to cause "lumpy" apples is an insect called the Apple Maggot (Rhagoletis pomonella). The lumpiness is caused by the tunneling of the immature stage (maggot). If you cut into the apple, you might be able to find their tunnels. See this MSU Extension page for more information: https://www.canr.msu.edu/ipm/diseases/apple_maggot

Another possibility would be feeding from insect like stink bugs (Hemiptera, pentatomidae). Stink bugs and their relatives the plant bugs (Miridae), sometimes pierce the skin of apples and cause a dimpling of the surface. You can read more about them here: https://www.canr.msu.edu/news/look_a_like_late_season_apple_damage

Thank you for the information, I will be checking the sites you mentioned.