Cuts and bruises

The other day my mom told me she was using some മുറിവെണ്ണ. I found it a bit funny since we can split മുറിവെണ്ണ in two ways.

One is മുറിവെണ്ണ = മുറി + വെണ്ണ meaning a piece of butter :-)
Of course, the correct split is മുറിവെണ്ണ = മുറിവ് + എണ്ണ meaning oil for a cut.

We see the same root മുറി in other common words like തേങ്ങാമുറി = a half of a coconut. A "room" is called മുറി - of course, you 'cut the house' into rooms.

The mallu word for bruise is പരുക്ക് . I don't really know the etymology of that. May be it is related to പരുപരുത്ത, meaning "rough". Perhaps, പരുക്ക് refers to the scar left behind after a bruise. Any ideas?