V-shape vein on my forehead. Tried sclerotherapy and vascular laser with no results, would dermal fillers work? (photos)

I would retreat your forehead veins with sclerotherapy.  The success of forehead  veins resolution depends on many factors but, most importantly, the experience of the doctor treating these veins.  Topical laser has no role here.  I usually use a butterfly and  STS with excellent results.  In addition compression during the procedure and following are also very important.  Sometimes I also make microincisions or punctures at the hairline to adequately drain the vein.

Hello,
The sclerotherapy solution used was probably not strong enough, and laser has no role in this kind of veins. It is a dangerous area that requires a vascular physician trained for this technique. 
A couple of sessions may be necessary if the Dr uses a correct protocol. A vein avulsion is also possible but there is increased risk of scar and more downtime. 

In our office we use a combination of foam sclerotherapy and phlebectomy (a minimally invasive removal performed using local anesthetic and a 1 mm incision at the hairline). Regular sclerotherapy is probably not potent enough and I have not seen a laser with sufficient energy to treat a vein of this caliber. Whomever you go to, make sure they have done it before as the drainage from this area can have connections to drainage to the eyes or brain and may also communicate with the blood supply of the scalp (which, if injured, could lead to the death of the skin in this area). Good luck.

Forehead veins such as those shown become prominent while laughing and smiling as those activities increase venous pressure.  I  treat veins such as those with a combination of foam sclerotherapy and a microphlebectomy.  If the veins do not look red and irritated shortly after the injection of the sclerosing agent, then it is unlikely to be effective and should be repeated or the vein should be removed at that point.

Forehead and facial veins can be difficult to treat.  We have to balance how aggressive a therapy to use with possible complications.  In your case, the veins appear very large and prominent.  Sclerotherapy would be a good starting point, but if that did not work I would advance to microphlebectomy +/- more sclerotherapy.Microphlenbectomy would involve making a tiny incision or needle hole and using a small hook to remove a portion of the vein.  This would disrupt the flow and hopefully allow the rest of it to shrink up and go away.  I usually try to do this at the hair line so no scar is visible.Good luck to you,Dr. Powell