How to tell if this is body dysmorphic disorder?

Excessive concern: If you are preoccupied with a defect in your appearance (imagined or slight), and this causes impairment in social, occupational, or other important areas of functioning, you might be diagnosed with body dysmorphic disorder. That is, unless your preoccupation is better explained by another mental disorder. Make an appointment with a mental health professional (e.g., psychiatrist or psychologist).

Body dysmorphia: Psychological evaluation can determine if you have this condition. Body dysmorphic disorder is a mental health disorder in which one becomes extremely focused on perceived body/ facial defects that don't actually exist. It can damage self esteem and quality of life. Cognitive behavioral therapy is a good choice for treatment.