What a 2/5 rating means
On the comedogenic scale, a 2 is still within the non-comedogenic range that dermatologists generally consider low-risk. That places Camphor in the range most people, including many with acne-prone skin, tolerate well.
One thing the number cannot tell you is concentration. Ingredients are listed in descending order, so Camphor near the end of a label is present in tiny amounts and matters far less than the same ingredient near the top.
About Camphor
It is an active ingredient included for a specific skin benefit. A cooling, mildly medicinal ingredient rated 2/5 on both axes.
Camphor in makeup and skincare
It is formulated into targeted treatments and some makeup-skincare hybrids. Its irritancy is rated separately at 2/5, which is low.