I don't know anything about the Restor a Finish however I'm a furniture refinisher. Can you post some pictures? How old is the heat mark? The heat mark is actually moisture which was drawn out of the wood under the finish. If it is a new mark try laying several paper towels on the spot and run a hot iron over it. Often the moisture can be drawn through the finish into the paper towel. Another thing you might do is put a small drop of lacquer thinner on the finish in an inconspicuous place and see if it wrinkles up the finish or dissolves it. It will get sticky if it does. This would determine if the finish is lacquer or could be shellac. What you could do if lacquer or shellac is pour a puddle of lacquer thinner on the heat mark and let it set until it dries. Often with lacquer you can melt the finish and it would melt through the heat spot too. It will leave an unusual spot on the finish when dry but can be rubbed out.