My sweater pattern calls for # 4 1/2 needles for body and #5 for sleeves…I mistakenly used the 5 for the body and know I don’t know how to compensate the needles for the sleeves
Welcome to the forum!
What pattern are you following? Can you give us a name or a link?
It’s not a big difference in needle size but it really depends on the pattern stitch and your gauge.
The pattern uses the smaller needle (4.5mm, #7) for the rib on sleeves, front and back. The larger needle (5mm, #8) is used for the body and sleeves above the rib.
If you like the way the body turned out ( ribbing and size of sweater) then just continue on with the 5mm needles for the entire sleeve.