come back—
1. return to a place:
- I’m going away and I may never come back.
2. become fashionable again; be restored:
- Some people would be glad to see corporal punishment come back.
3. return to the memory:
- At first I could not remember why everything seemed so familiar; then it all came back.
go back—
1. = come back 1:
- You should never go back, they say, to the scene of your past romance.
2. (of troops) move backwards; retreat:
- Our army had to go back a few miles when the enemy won an advantage.
3. return to work after a strike:
- I’ll be glad when the post office workers go back, it’s very difficult not getting any letters.