Just run it then.
If it works it works, even if it's missing 25% or more of the output, which it probably is.
After a grow or 2 they all have considerable loss of lumens per watt.
Even noticeable by eye, when side by side with a brand new bulb.
Should get a new one though, when you can..
You're gonna be losing more than $30 in electricity thats putting out extra heat instead of light, and risking having to run to the hardware store and paying 60 + tax if it the bulb craps out mid flower.
It's all a gamble anyway right?