Lasers work because the pigment in the skin absorbs the laser light and generates heat. If your eyebrows are dark they also will absorb the laser energy if the tattoo happens to be over them and your will risk loss of the eyebrow hair. It is possible to transplant single hairs to restore eyebrows (and this is commonly done by experienced hair restoration surgeons. So if the tattoo removal is more critical than loss of the eyebrow and you can tolerate the added procedure and costs of the hair restoration to the eyebrow, then that may be a consideration. You should wait at least 3 months after tattoo removal before doing the eyebrow restoration, as some of the hairs may only temporarily be lost and start growing back, but the deficit of hair in the brwo can be observed and treated.