Hi SB I had the same problem with DD thanks to antibiotics during labour. I found nilstat didn't work and had to change to daktarin gel, you have to be careful administering it as it is a gel and if you use too much there is a risk of choking. I would measure out a dose then use a cotton bud to apply it to her mouth after a feed. I used canasten cream for myslef after feeds 2-3 times a day and I would wash my nipple with a warm face washer and water before a feed. I also find taking probiotics works well, I believe that there are also some available for young children but would check with your doctor/pharmacist about what age they can take these. I think the thrusk went about a week after I changed to the daktarin gel.

Good luck, I know how painful and frustrating it can be.