[Hectic]

Does it have a set/grub screw on it? If it does itll take a small alen key like 1mm or 0.5mm.
If there is no set screw is it an orange one? Plastic? If its plastic try sprayin some lube like pure silicone oil and let it sit a bit then use a wrench on ghe hider and a pare of vice vrips on the barrel with a rag or a few layers of tape to protect it or try soaking it in hot water and use the same method.
If it is metal heat it wil a torch or butane lighter or even on the stove, be sure to protect you hands when u grab it while its hot and use the same wrench method.
It is likely glued or loctited ln there. Especially if it is an orange one.