Detergent Spill Left Lighter Spots on Pants?

Whilst using Jik (detergent) on a white top I accidentally dropped a few specks on my new navy pants which have shown up like a plum colour. They are very small, but it now looks like the pants are dirty.

Does anyone have any suggestions how I can fix this? I was thinking, perhaps using a navy pen? or dye? which might be tricky in trying to match up the exact colour navy. I would appreciate any help you might have.
Regards from SA.

By Reinet from South Africa