Drinking ice cold water doesn't help very much. It just burns your burn. Let your tongue "rest" for a few minutes. Then try drinking some plain old water, not ice cold. If that doesn't help, try sucking on an ice cube.
I burned my tongue on hot chocolate recently...I tried everything I could think of to make it stop hurting. Nothing helped I even tried lidocaine and it did nothing....I remembered that my kids dentist recommended Orabase so I coated the tip of my tongue with it and it took a little while but it helped...I still have that weird scorched feeling but its not hurting.