Hi,

It sounds really painful. And after you have been breastfeeding for so long, so well. Hopefully you can clear up the nipple quite quickly. It is likely that everything that has happened over the last few weeks IS related. It may take a little while to tease out what is chicken and what is egg. Firstly, is the infection in your baby's mouth thrush? I'm thinking not. Do you know what it is? Is it being treated? How? How was the thrush diagnosed? Are you still on the ABs for the mastitis?
Lansinoh is not antibacterial in itself. It can be helpful in keeping nipples supple in the early days, in particular, and many mothers report it to be soothing, but there is no real healing agent in there. Usually nipple cracks heal fairly quickly if there is not infection (fungal or bacterial) because the breastmilk has growth factors and is somewhat antibacterial. Sometimes it is difficult to tell by looking what is going on in there. Some mothers find that an ointment like kenacomb with has a 3 way action (antibacterial, antifungal and steroid) really helps in these situations. You must get it on prescription from the dr, and they will tell you to wipe it off before feeds - in fact, more because it tastes bad than it being particularly bad for the baby.
Hope things are better soon
Warm Regards
Barb