I think washes are important, and can really change the way your wracks look "built" by their haemo.
Start off with something like kislev flesh. Not too dark, not too pale.
Highlight it maybe once, careful with all those little strips of flesh, then experiment with inks!
Red gives a raw, recently grown flesh look, purple looks mad bruised and battered, green appears sickly and rotten and just ugh, and blue looks the most corpse-like.
Then highlight it again, as normal. After that, you can take one of the colours you didn't use for a wash, and apply patches of inflamed skin around implants, or localised bruises, or anything. Patches of grey mould, who knows. Better using thinned paint than ink for those bits.
Dark Angels. The Rock. Lion El "Dwayne" Jonson. I can't be the first person to have thought of this.