Hi.. Thanks for the query.. Tastelessness at the centre of tongue can be due to damage or loss of papillae that contains taste buds and this can occur due to causes like side effect of medication that can cause inflammation of tongue, dry mouth, oral thrush etc.. If you have taken any medicines like antibiotics, steroids etc then it can cause oral thrush which inturn can damage the tongue papillae.. Thrush represents as a white coating on tongue so in case if it is present it can be due to Thrush. So first of all consult an Oral Physician and get evaluated and a thorough clinical evaluation of tongue should be done.. Once the cause is ruled out it can be treated for relieving the symptoms.. As of now keep your tongue clean using a tongue cleaner.. Gargle with warm salt water.. Chew sugar free chewing gums and drink plenty of water.. Hope this helps.. Regards..