Each LED draws 30 mA. As I am typing this, 3 LEDs are glowing normally.What is the maximum amperage I can draw through the Arduino Uno? Will I burn the board if I have 15 LEDs?
15*30 = 450
Although each I/O port can source more than the test conditions (20 mA at VCC = 5V, 10 mA at VCC = 3V) under steady state conditions (non-transient) ... Pins are not guaranteed to source current greater than the listed test condition.
The neopixel are powered from the 5V header pin, yes? They only receive signal from the 328P, so no damage there. Kinda surprised you didn't smoke the 5V regulator, which is only rated for 800mA.