Can i cut off a skin tag myself? will it hurt?

Not Advised: 1) it may not be a skin tag 2) if you don't cut off a skin tag in exactly the correct place, it will hurt and bleed.

String: If you have a skin tag or lesion with a narrow base, and you are sure it is not malignant, a useful way to deal with it is to take a length of stout thread (you might need a helper for this), and lasso the base with a loop of the thread, tie is tightly with 2-3 knots, cover with a piece of tape and wait a week for it to fall off without leaving a scar.

Yes: If you don't pull it up-"tenting the skin", use a sharp sterile scissor, and treat the skin to sterilize it . You can do this.