That is cochineal scale but it will not release the same red dye that the softer insects produce. It's a really really bad infestation. I would not keep the plant. The bugs are contagious and you will have to remove them all mechanically if you want to keep the plant. To do this, fill a small cup with 70% ethanol or insecticidal soap (1-2% mild kitchen soap will work for this purpose) and dip a toothbrush in this before using it to scrub the surface of the plant. Physical removal is most of the solution, but you will have to be vigilant and remove the bugs again when they come back (as they inevitably will, given the state of affairs). After the bugs are gone there will be small scars where each of the larger ones latched on to the stem, so the plant will probably be disfigured for life. So it's not a great prognosis even under the best of conditions.
