The only constant in life if that everything must chance. Any treatment is subject to changes over time. The main problem with bone grafts is that we typically see up to 40-50% resorption of the graft within the first year. Even after implants are placed in the draft and it is in service, we still see some resorption overtime. This is the reason why surgeons typically overbuild the graft as much as possible. In addition very careful monitoring and cleaning of the area are a must. At this point, you should see a qualified periodontist or oral surgeon to evaluate what can be done whether to restore the bone and tissue to the area, which is typically very difficult, or to maintain the situation at this level very carefully.