When profiles are merged, the manager(s) of each become the managers of the merged profile, so none of you loses your management.
If you are outside the profile's Max Family, someone within the profile's Max Family can remove you as a Manager. But if you are within the profile's Max Family, then nobody but you can remove you as manager. AND you can add yourself as manager of profiles in your Max Family (as long as its not a Geni user)
If instead of merging, someone deleted profiles you added, you can find and undelete: https://www.geni.com/list/deleted