Newbie here who has never grown a beard until now. I have patches of no-growth areas on my cheeks and was wondering how to fill it in. Are there are any spray on/application products to but fake hair in there (something like Toppik)? Also, lots of grey hair and used Just for Men but it doesn't last for more than a week (gray comes back after showers). Any recommendations for darkening gray hair for the long haul? Thanks!