The bad news is this is probably close to the worst time of the year for this type of misfortune to befall your plant. The good news is Ficus elastica (aka rubber tree) is genetically vigorous by nature and usually rebounds quickly from having even considerable indignities heaped upon it.
Since what remains of the plant looks pretty healthy, the plant probably has enough energy reserves to push a fresh flush of foliage on the remains.There is a growth regulator (auxin) produced primarily in the growing tips of branches (in apical meristems), but also in leaves. One of this growth regulator's primary jobs is to suppresses branching and the formation of new leaves anywhere but at the apical meristem (branch tip). When the leaves or the branch tip are removed, another growth regulator (cytokinin) becomes dominant. This stimulates branching and new leaf formation. The key is whether the tree has enough energy stored to produce new foliage. Luckily, there is foliage remaining on the tree, which also produces food/energy to help the plant along.
Keep the plant warm (65*+) and in good light for fastest recovery. Be very careful that you don't over-water. With the foliage volume reduced, transpiration and water usage will also be reduced and root rot becomes something to guard against more judiciously.
Al
