I have had ME for just over three decades now and slow healing was one of the first symptoms I noticed. Prior to being chronic I healed fairly fast, but since then my skin seems to be the old guy crossing the road while my life is one of the cars at the lights, honking him to hurry up. I bruise easier than I should and the scars from even minor cuts and scrapes hang around on my body like tatoos.
Like many of my other symptoms though, I'm blessed that, though the healing has got worse, the decline has been gradual. Apart from a persistent ten-year old wart on my thigh which has even resisted repeated freezing, I've never had to be offerred supplements or specific treatments to repair a wound and my lovely-pretty boy face still heals normally
A strange addition to the healing and bruising has occurred over the last couple of years. If I am using any kind of electrical tool for more than a few minutes or engaging muscles in a specific activity for any length of time - using a handsaw say - I will bruise at the location of the most active muscles. The first time it happened was the worse for obvious reasons because I was unaware of the chance of it happening, and have got used to shrugging off and going through the constant fibro pain barrier in order to get things done. So the bruise swelled to the size of a golf ball and took about two weeks to disappear. Ever since, I have been careful to limit my activities. I don't attempt much DIY, now for brainfog reasons, mostly but whenever I feel pain during a stretch or strain activity I stop. I'm even wary stirring porridge nowadays - I kid you not.
I believe some kind of Vitamin D dysfunction is at play because the healing and bruising is worse in winter for me than summer - however, non-sunlight Vit D supplement does nothing for me -on any level.