I would leave the width as is. I would then drill out the knot carefully, starting with a narrow drill bit. Then increase the diameter of the drill bit until the knot is fully removed. Glue in a small hand carved dowel from a scrap of heartwood. Hard to tell from the photos if you have already done that or not?
I would still treat it as a weak spot, and leave a small swelling around that area as I continued to tiller.
Personally never made a bow from juniper, but from what I have heard the ones that last are always backed with something else like rawhide, sinew, or even hickory.