White cobweb type mould after leak

[Iknowitsyou]

Hi everyone,
I had a leak from my toilet about 2 weeks ago. Pretty sure with the rate it was leaking it was fixed within 2-3 days max. Today I noticed that the bottom of the wall is covered in a spiders web type mould. Although a yellowish/white when wiped left some dark almost black marks on the cloth. Unfortunately it’s went up the back of a cabinet attached to the wall so will need to get that back off the wall. This wall is papered so I’m thinking I need to remove that and give it a good clean. I’ve never came across mould like this has anyone got any tips? Stupidly never thought to take a photo first.
This is a downstairs toilet, house less that 10 years old, no toilet window just an extractor.

Tried looking online but freaking myself out reading about structural integrity etc so hoping someone here has tips for what to do!

thanks

"How Do You Kill Dry Rot Fungus? | Garratt's Damp & Timber" https://garrattsdamp.com/blog/how-do-you-kill-dry-rot-fungus/

"Identifying Wet Rot | What Are The Signs of Wet Rot | Timberwise" https://www.timberwise.co.uk/wet-rot/identifying-wet-rot/

Thanks @justasking111
The leak was coming from the cistern and dripping down the floor is tiled and wasn’t very wet when discovered and we put a bucket down straight away.

This mould appears to be on the wallpaper not the skirting board at all and no smell, soft wood or the likes. Would those take hold in such a short time frame?

😩 hope it’s not either of those!

Wet rot is preferable. Either way you need to sort it fast. It could have been leaking out of sight for ages.

Will do thanks

This is the mould behind the cabinet. All cleaned down now, wallpaper off after work tonight to see if any further damage. No smells or cracked soft wood that’s visible though could be somewhere I can’t see! 😭