You are, thinking reasonably, allowed to use at most 8-10 lights in the scene. Due to the way three calculates light information - using more than that will start dragging the performance down (the lower-end the device, the faster FPS will converge to 0.)
What you can consider is to create a pool of 8 PointLights, and use them to lit up only the lights that are close enough to the camera (if a light would be too far away, it would not be visible and would not affect the materials in the scene.)
And if you really need tons of lights - your best bet would be to go either with this, or pinging @DolphinIQ so he’d teach you how to write a DeferredRenderer for three.js (deferred rendering allows almost and unlimited amount of lights in the scene, but has it’s own pros and cons.)