I was trying to crochet a plushie but didn’t have safety eyes so now it has no eyes
You’d have to use fabric or hot glue if you don’t want to undo the finish knot
Another option if you don’t have access to hot glue could be to embroider the face on it either with embroider thread or yarn
I do hot glue
I’ve seen people use safety eyes after finishing a plush by slipping the backing through the stitches, but I think that would depend on your tension and yarn size. I’ve done it before but it is very difficult. Generally if I don’t put it in during the process, I just end up embroidering for ease, but if you’re not worried about them being treated rough, you could definitely try gluing them in. Just remember that safety eyes, whether using the proper backing or glued in, are still not considered safe for little littles. The backs can tend to be flexible and still come off if tugged hard enough.
I use tacky glue!