You can certainly remove HA paste, just as you can remove bone. You just shave it down. It's just more surgery and every time soft tissue is cut, it gets a little more f**ked up when it doesn't heal like new. There's a study on pubmed claiming the resorption was the biggest problem with HA paste, up to 20-25% of cases in the short term. Long term resorption rates remain to be seen but there will likely be some. It's bone like but it's not bone so probably won't change at the same rate as bone underneath. The product is too new and sample size too small to know what 20-40 years will do to it. Natural bone resorbs too so it's not a relative disadvantage, just that what looks good at 20 may not look good enough anymore at 40 or 60. Aesthetics has a shelf life. The only real permanent solution is to not have had problems to begin with. You can thank your parents for that.