'Paint burning' effect I'm a 2d animator by default but was asked to create a 3d animation in Blender, with only bare basics at my disposal the request seems rather daunting. I need to recreate the effect of paint burning, like here - https://youtu.be/tsgPh4tBz9U?t=45 It's the 'bubbling up' effect and change of colours of the whole thing later on that scares me.
To me this is black magic, but my first line of thinking is to copy the outer layer of the pipe and make this into a particle system that fades up circular particles with growing size over time, as with the colours I know I can change the colours in shading tab over time.
My question is - is this right/ the best way to approach this, if not, can you recommend any tutorial that can open my eyes a little bit?
I realize how time consuming it would be to explain this to me so I'm not asking for definite answers but at least some form of direction where to start would be greatly appreciated. If you know of an effect that can help or if you have seen a tutorial somewhere that covers similar problem I'd be really grateful.
You might be able to do it that way, but I think I would make use of microdisplacement for the model.
I would recommend a tutorial but I can't find anything recent on it right now.  I'll just give you a quick and dirty rundown of the settings you need.
Cycles render engine
I recommend experimental feature set

I created a cylinder and added some loop cuts just to even out the geometry that our subdivision modifier is going to add.

Add a subdivision modifier and set it to something fairly high.

We can choose to use Adaptive here, it's available if you checked Experimental.  You may want to use this for rendering if you run into memory problems.
Add a material and then go into the material settings to enable displacement.

This is a node group I threw together just to get a decent example for you; something with some bigger globs and fine crunchy detail.

You could use an ambient occlusion map to guide the discoloration.  There's a lot more you can do here, but hopefully this will give you a starting point.