A tiny mark on a lens often matters less than it seems.

If the defect is on the front element, it will usually make no visible difference in normal photos. At most, it could contribute a little flare, but you’d likely never notice it.

If the defect is on the rear element, it has a greater chance of causing flare, especially when shooting toward a bright light source in or near the frame.

So the practical test is simple: take photos in normal conditions and also toward bright light. If you don’t see any effect, it may not be worth worrying about for image quality.

That said, if the lens is new and the mark concerns you, returning or exchanging it is reasonable—particularly for peace of mind or future resale value. The provided answers do not support predicting that a tiny chip will spread into major damage, so image impact is the main concern rather than imminent failure.

In short: front element = usually negligible; rear element = more likely to affect flare; new lens + concern = exchange if possible.