Relax. Read the following desciption of the phenomenon:
"Sun spots. Another "spot" a cigar gets is called by various names. Sun spots, water spots, rain spots. A nice green, blue-green or aquamarine spot on your cigars, especially if you are looking at a Havana, is a very common occurance. These spots will have a clearly defined edge to them. If you look at them sideways, the spot will not rise above the cigar the way mold does because sun spots are a part of the wrapper. If your wrapper has a nice oily sheen, sun spots will have the same oily sheen to them as the rest of the cigar. These spots are natural, a part of the leaf, and nothing to worry about. Some people even use them as an indicator of authenticity for Cuban cigars."