Mould between ceiling board and loft insulation

[Guy1228]

Hi all, we've recently developed small patches of damp in one corner of our bedroom, although not damp to the touch. I've inspected the loft and seen beneath the old insulation is a lot of mould that looks like it's been there for some time. Does it look too bad to keep or should I let it dry out completely and put down new, thicker insulation?