I finally visited another oral surgeon, who seemed to be more experienced with these kind of issues.
I told him my case and about my failed apicoectomy he said I should have had performed a re-root canal treatment along with the apicoectomy, which I think it's a better approach than the apicoectomy alone (point in favor).
I asked him about the exposure and he said that the bone graft should have been placed higher, that probably the surgeon didn't have enough periosteum to cover the graft and then the exposure took place (second point in favor).
He now asked me for a digital Rx to see how much bone looks vital and see if there would be enough soft tissue to cover it. Here are the Rx's thought I haven't showed them yet (next appointment its in one week).