I have a pea size lump that formed by stitches right below my left nostril? Is it a hematoma?

I my doctor says it will go down in size but it has been four weeks since the surgery was performed to get rid of a cyst inside the center of my lips. The stitches were both inside and outside my lip up to my nose and the bump formed just above the stitches , right under my left nostril?

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