If it was water spots like mentioned it would be in more places then one leaf. My best guess after looking online is pest damage. Check for spider mites. But looks remarkably close to "leafhopper" damage. Can send you a picture if you want to DM.
Hello,
Are there white spots only on this leaf? I would say that a few droplets stayed on the leaf and it may have burned a little, nothing serious. Be careful not to wet your leaves.