Hi.. Thanks for the query.. Well, the symptoms of having white coating over the tongue along with roughness, irritation and soreness on tongue tip is most commonly due to fungal infection known as Oral Thrush along with Stomatitis and Glossitis.... Many a times even after resolution of the white coating there is inflammation leading to pain and soreness.. You should consult an Oral Physician and get evaluated and if Thrush is still present as diagnosis then you can advise you to take antifungal medicines like Fluconazole or Itraconazole orally.. Nystatin mouthwash and clotrimazole lozenges can be advised.. Taking more of probiotics like Yoghurt and Garlic will help in faster clearing of fungus.. Drink plenty of water to prevent Dry mouth that is common in Thrush.. For soreness in mouth you can gargle with Lidocaine mouthwash and also start taking Vitamin B complex daily.. Suck ice lollies to reduce inflammation and avoid spicy foods.. Hope this information helps.. If you have further questions you can visit my profile and ask me a direct questions for a detailed discussion.. Regards..