Are there different quality Botox needles?

Yes, needles vary . I doubt that size is the issue because I don't know anyone that uses a needle thicker than a 30G and a bigger needle might also be more likely to drip bigger drips and nobody wants to waste even a drop. However, needle quality varies a lot and there are sharper and duller needles. A needle that came out of same box as another might not even be identical and I sometimes throw one out after one stick when I don't think that it is quite right. Doing many injections with same needle dulls it. If you reconstitute your Botox with saline that is not bacteriostatic, it hurts like the devil.  your Botox

Pain with botox injections varies greatly with technique, needle size, and diluent of the product.   Larger needles, high volume injections, multiple injections with the same needle and use of a diluent that doesn't have bacteriostatic solution can all hurt worse.   The other major factor is with needles used to draw up solution that accidentally hit the glass of the vial and cause a burr.  

Most patients should have no trouble tolerating botox injections with the pain level rated as minimal to mild. Typically the skill of the injector is far more important the the gauge of the needle. If you continue to experience significant discomfort with your subsequent botox treatments, it would be wise to consider another injector.