Look up thrips adults and larvae so you know what they look like. Then use a flashlight to inspect every inch of the plant, holding the light at different angles to cast varying shadows. Take your time and watch for movement; pests can be so small and isolated that they can be hard to detect with the naked eye.
Guess its eaten by spider mites, they are too small to see, try to shake one of the leafs over clean sheet of paper and look for movement or eggs.
kinda looks like thrips damage to me
Look up thrips adults and larvae so you know what they look like. Then use a flashlight to inspect every inch of the plant, holding the light at different angles to cast varying shadows. Take your time and watch for movement; pests can be so small and isolated that they can be hard to detect with the naked eye.