Dark spots on roof of mouth

Age: 35

Sex: Female

Height: 153

Weight:77

Race: Asian

Duration of complaint: 1 day

Location: roof of mouth

Any existing relevant medical issues: no

Current medications: none

Include a photo if relevant

Hello all. Before my dentist put on my braces, she requested me a panoramic and photograph of my teeth. When i saw the photos, there are 2 dark spots on the roof my mouth. I haven’t noticed it before as this is my first time with having my teeth/mouth taking photos. She examined the dark spots and mentioned not to worry as she can’t feel any bumps or whatever. I dont feel sick or anything and perfectly fine. But to ease my mind, she mentioned she will also consult her mentor but for the meantime, there’s nothing to worry about it. Does anyone experience this? B