Perspiration can be corrosive (acidic or alkali) and could etch some metal. Aluminum is particularly vulnerable to corrosives. Nickel is very resistive to it.
I haven't had that problem with my metal needles yet, but my Timex wrist watch (3 yo) has rough edges on the base metal bezel from perspiration corrosion but the stainless steel back is perfectly fine.
If your needles are etched, then a fine sand paper may help smooth them out. By fine I mean 600 grit or larger (the bigger the number the finer the grit). Sanding will make the needle smaller. I have only used sand paper on wooden needles. YMMV.
Needle sizes differ between brands. It is even more noticeable with crochet hooks. If the plating is flaking off, it can easily make a difference of 0.01 (one hundredth of an inch or 0.25 mm) in reduced size.