recently installed a new kitchen sink and replaced the drain. since then,
there is a horrible odor coming from under the skin near the drain. should I
guess that it is not properly draining the fumes. how can I rememdy this?

Jamie,

When you did this plumbing you should have installed a U shaped pipe
called a "trap". The trap is meant to hold water which will prevent sewer
gas from flowing up the drain pipe. If the trap is empty it won't do this so
run some water down the drain to fill the trap. If you did not install a
trap then you need to redo your plumbing.

Dave M.