The reality is your binders are too small in size, if it is leaving bruising especially (and the pain you describe after removing it, this should not happen) . Only solution would be to exchange them for a size up or see if you could get a discount if you cant exchange them, there is no other 'fix'. Long term use can lead to serious health problems and an inability to bind comfortably.
The oozy rash I've never heard of my self, I would recommend asking your gp (doctor) about it, could be the material constricting breathing of the skin due to it being to small.
I know it feels great and to walk with confidence but this is your health, well being, and it can take a drastic turn if you bind wrong, trust me, a lot of my friends have been through this.