I downloaded this model from turbosquid, I converted the textures to tgas and imported it (its a 3ds) to MED but this has happened:

can anyone tell me how to fix this?
It also happened with a custom models face (all the other textures are fine but his face is messed up)

Any help would be greatly appreciated.

Hello!
I´m not familiar with importing 3ds models, but the first thing, I would try in such case: select the faces, that don´t show the skin and klick on the "flip normals" - button in MED. Normals often get messed up, when importing models. It´s however strange, that they appear black ...

It's not the incorrect normals, but rather that your texures UV's were imported incorrectly...

Even if the file is a 3DS file, different programs may store their data slightly differently.

I see, any idea how I can correct this?

Take a look into the UV Editor: are the UV coordinates switched vertically? This happens often to me when I import from an obj file.

which MED do you use? maybe you use an older version (3DGS<=6.31) that does not support multiple skins.
i see it's a 3ds, try to load it in wings3d and see if the textures are correctly aligned.