After seeing the image it seems to be normal.. tongue is a highly vascular part which has more keratinized on dorsal surface so it looks white and very mild keratinized on ventral side..the lingual veins and artery enter the tongue from ventral side..that is why the looks red in the floor of the mouth and bluish gray on ventral surface of tongue.. and soft tissue band starting from ventral surface to floor of mouth is the lingual frenum which is more prominent ..it looks like normal..
Next Steps
please don't palpate and check the lower side because it may further make the mucosa red
Health Tips
please visit the dentist the exact final diagnosis