Under bust wetness is uncomfortable and can be unhealthy. It can lead to a yeast-like rash under the bust, not to mention how it affects your clothing.
Powder fell on the floor the other morning and it reminded me that we all need help when it comes to issues of the bust. For the under bust sweat, there are products to address it; like creams that turn to powder, baby powder or cornstarch. We all have tried something. And some use a lot!
An alternative approach is to use products designed for the "other" end. Panty liners are one trick. Double them up back-to-back and take their wings off, (Sounds mean, doesn't it?), and put the panty liners under the bust, tucked into the bra band. Or it can be used to line the bra cups too. I have used tampons stuffed into my cups!
Back in the day, the beautiful hankie played it's part in mopping boob sweat and keeping ladies comfortable. However, the absolute, most simple solution is to get the bust off the chest wall. Elevation and support remedy the need to use the powders, creams, or re-directed panty liners.