I hate when that happens and the plaster is all wet on the floor.
Fun fact: Band-aid is a brand name by J&J company. They're actually adhesive bandages. But, in american we all just grew up calling them band-aids. We also call lip balm "chapstick" (which is another name brand).
The common word for band aid in the UK is plaster, and should be accepted.
Can plaster also mean a cast?
According to an online translator, plaster cast translates to "gips". Can a native/proficient speaker confirm/deny this?
Yes, they're called "gips" - which is also our name for the gypsum from which the plaster is made.
I'm sorry, but how exactly does the pronunciation of 'plasteret' differ from the pronunciation of 'plastre'?
"plast-e-re" vs. "plast-re"
Yes, I hear it now. Schwas can always be deceiving, unfortunately.