Lately I edited some questions to improve them and I got 2 reps per edit. Now 4 of them are gone.
When I edit a post I get 2 reps. When after that someone else edits the same post, do I lose those reps I got?
No, additional edits following yours will not lose you the rep you gained.
The likely cause is that the posts you edited got removed and this is usually reflected in your profile under the reputation tab. See the below image:
One possible reason that you do not see