Filing through the drilled hole and collapsing the screw is the safest approach. Another option is a jeweller's saw, threaded through the hole. Don't know where you are, but any jewellery supply will have tools you need. Michael's or an art supply as also possibilities. Automotive stuff is mostly too large for our scale of work. Alternately, get the smallest fine file you can, then grind most of it away until it fits.
I would assume that Loctite is present and warm it it before trying anything else. Spot warm with a small metal rod, heated on your stove top. Use pliers! You may be able to turn it out with a fine centre punch.