The swelling of the vein following close injection of a filler is most likely due to compression of the vein either by swelling post filler or extrinsic compression of the area above the draining site of the vein. I would just allow time for this to resolve on its own. If it is due to swelling then this will resolve soon. If due to compression then it will take longer.
Possibly the juvedrm is constricting the vein a little. Massage the area well and consistently and this should go away. If it persists go and see you PHYSICIAN injector. I believe this is a very temporary issue. My Best, Dr C