The reason why I'm asking is that I'm trying to RP a S4 vamp and IMO healing spells would actually kill me so I use potions instead and I haven't touched restoration but I might if it affected alteration.
Yes, it will increase the duration of your flesh spells 50% and increase magnitude by 25%.
Also for potions- it will increase duration and magnitude-
Also for any enchantments, 25% more effective. i.e. necklace of peerless wielding is 40% - for a vampire it is 50%.
This spills over into many other areas- you can smith better, you can do the "loop" better.
There are also a bunch of tricks to circumvent any weaknesses. Being a vampire is great.
In conclusion: you doing a vampire- you should touch restoration, if just to pick up necromage- and while you are there pick up the regeneration perks- that will refill your day-stunted magica.