[SunHELP] Devices in /dev/dsk

Hello,
I am hoping that someone here can help me find out the right way to add
devices to the /dev/dsk area.  Someone here got an error about a full
disk...instead of going to /opt/.... they went to /dev/dsk and removed
c1t4d0s0.  I can still access the data on the drive (I am not sure what
damage this might/might have caused, I assume if the machine was rebooted a
problem might occur). Anyway can anyone suggest away to fix this that does
not require a reboot?
I am not the sys admin here...although I have had a few years of sys admin
work...but I am jut trying to fix this for him 'under the radar' so to speak
and want to make sure that I don't make it worse for him or me.

Thanks,