I think, really, it's a goner. If the gloss is still wet you can try to take it up with white spirit or cellulose thinners, but once it's combined with the fibres that's probably not possible. (And if it's delicate or synthetic, spirits and thinners could melt the fabric!)
You could try massaging Swarfega Paint (you can get this from DIY shops or if you have a mechanic/body shop nearby, duck in and ask for a squidge) into the fabric and then washing again.
I've heard of (extended family of builders, here) a product called Paintex, which I have never tried, but once you're into specialist cleaning products you may as well buy a new-to-you jumper on eBay.