She needs something else to pacify her,
try putting 2 mittens on the same hand
my sons grandmother used had to put masking tape ( the thick painters tape kind) on it aswell because her son would suck thru the mitten but the tape on the outside was a good deterent,
Annoying to the child but helpful for the times when he couldn't control the sucking urge.
nothing else really worked, because the hot peper and things wear off, or they build a tolerance to the taste.
During the day is easier becasue lollipops work well, however it still contributes to the sucking urge so start with pops, then work to reeses peices candy or M&M's less sucky kind of candy, and then healthy treats.
the night is the most difficult to control.
Good luck
M