P.R.
My daughter (13 months) is a thumb sucker too. I am also trying to get rid of it . My problem with this girl is she uses both her hands.
Here is what I did with my elder one while she was sucking her thumb and it had started looking like a piece of meat. First of all I use to hold her hand and stop her for sucking her thumb , apply lanolin it heals . I used " Thum Liquid 0.2 oz" it stops thumb sucking and nail biting, available in CVS and on Amazon for 3 bucks. As soon the thumb heals brush it on the thumb day and night .
It will take atlest 15 days , but she will stop thumb sucking forever. I know it is really hard , but I could not bear to see her thumb so I got rid of it completly.
Hope this helps you .