Your baby seems to be having thrush not responding to the treatment you have been using. Make sure you are taking care of the bottle hygiene i.e the bottle and the nipple are boiled before the feed after they have been cleaned and washed so that no particulate material is left on the bottle or the nipple. You may try clotrimazole lotion which comes by the name of Lotril, Clotrin. These are little bitter and the bottle says for external use only. Nonetheless they can be used in the oral cavity. Just instill few drops of this lotion onto the tongue and try to apply over areas if they are not easily accessible with the help of sterile earbud. Do this about 10 minutes before each feed and even when the thrush has cleared over 4-5 days continue to apply this for another 4-5 days 3-4 times a day. Similar application can be done on the breast nipple, but make sure you clean nipple with sterile water before the feeds other wise baby may reject the breast. See a pediatrician to make sure your baby is otherwise healthy and does not have any systemic deficiency or illness.