This is a question for your neurologist. PSW can mean a number of different things, especially important is whether they occur in conjunction with fibrillations or not. It appears you did not have fibs.
Try googling "Are fibrillation potentials and positive sharp waves the same? No."
Although in most cases these two potentials have the same clinical significance, there are at least five different situations in which they do not have an identical meaning: (1) positive sharp waves can be recorded earlier after a peripheral nerve injury than can fibrillation potentials; (2) occasionally, nonclinically significant diffuse positive sharp wave activity may be seen in the absence of fibrillation activity (i.e., "EMG disease"); (3) positive sharp waves may be seen in distal muscles of "normal" subjects without the presence of fibrillation activity or clinical significance; (4) positive sharp waves without fibrillation potentials may be seen following local muscle trauma; and (5) positive sharp waves may be seen alone in some demyelinating polyneuropathies.
So, as you can see, just saying you had one PSW is not nearly enough information. Did you have a recent peripheral nerve injusy or muscle trauma? Do you have any other signs of MG disease or a demyelinating polyneuropathy? Questions for your neuro...