So there are three things here. One, these may be nothing and there is no reason to start planning for the worst. Second, these may be new "primary" sites (if either happen to be melanoma) and that would mean they are unrelated to the original lesion. Or third, they could be a recurrence of the original. Recurrences don't typically look like a mole, however, although it is always good to check things out.
So if they are nothing, continue on. If they are new primaries, then a WLE/SLNB depending on depth. If this is a recurrence of the original, then further evaluation might be needed. A PET scan isn't useful in looking for new primaries, it is only good for showing tumors measuring about 5mm or larger. And unless one of these things would change your staging, it's unlikely a PET scan would be warranted. New primaries only change your staging if they are worse than your original – in other words you are the stage of your highest primary stage. I've had an in situ, stage 1a and stage 1b primary so I am considered stage 1b.
In determining tne makeup of a new primary vs a recurrence, one of the things the pathologist looks at is the growth patterns. In the very simplest terms, new primaries tend to grow from the top of the skin downward into the dermis. And a recurrence grows from the lymph vessels deeper in the skin either thru the dermal tissue and possibly upward to the surface.
Let us know how it goes, but don't start planning for the worst until you have confirmation it is warranted!
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