Thanks for sharing your concern.
Painless brown dots seen on the tongue is the called HAIRY tongue or black hairy tongue
This condition is characterised by hypertrophy of the filiform papillae of the tongue with lack of, normal desquamation which may be extensive and form a thick matted layer on the doorsal surface.
The colour of the papillae various from yelloish white to brown or even black depending upon their staining from such extrinsing factor as tobocco, certain foods, medicine or chromogenic organism of the oral cavity.
Sometimes antibiotic like AUREOMYCIN
, SODIUM PERBORATE, SODIUM PEROXIDE may cause this.
Are you smoking?
Discontinuation of the habit might help. This is the benign condition.
Food debris often collect deep between papillae and produces irriation of tongue. In such cases the TONGUE MAY BE BRUSHED with a tooth brush to promote desquamation and remove the debris.
Hope this helps