Is this stain on my filling or cavity?

This is my lower molar, have had this white filling since 2014.
Went to the hygienist few days ago.
But after going there I've noticed this on it.
Can a hygienist damage a filling?
Does it look like a stain or cavity?
Very anxious.
Is this stain on my filling or cavity?
Is this stain on my filling or cavity?
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