帰る(かえる) and 戻る(もどる) have similar meanings but are a little different.
Say, there are two places, place-1 and 2. An object is in place-1, moves to place-2, stay there for some duration, then moves back to place-1.
帰る(かえる)/戻る(もどる) both mean “move back”. The fundamental meanings are the same. However, in detail there are some differences.
戻る(もどる) implies that the duration of staying is relatively short.
戻る(もどる) can be used when the place-1 is just a temporal zone.
帰る(かえる) implies that place-1 is the home ground of the object.
戻る(もどる) can be used about value of something, not about physical moving.
For example, when you drove a car, you found a store. You stopped, got off and walked into the store. Then you noticed having no wallet, you left it in the car. So you had to move back to the car to take it. In this context, 戻る(もどる) is suitable, 帰る(かえる) sounds a little unnatural.
Because a car is not a permanent place, it is just a temporal zone.
If this story is about your house, instead of a car, then your house is a permanent place, so you can use both 帰る(かえる)/戻る(もどる).
■Value of something
In the following examples, “normal value” is not a physical place. It is a numerical value which indicates health status. Using 帰る(かえる) for that sounds unnatural. 戻る(もどる) is suitable.
The heart rate of the patient returned to normal value.