In my game the players left arm is this weird transparent color, but the right is normal. When i drag the right arm’s material over to the left it doesn’t fix the problem, so there’s something wrong with the object itself not the material. How do i fix this? I cannot show any pictures because i don’t know how to upload them.
The UV of the character might be messed up. If it isn’t then post some pictures.
Just drag the image file into the text box. That’s what I do.
When i open the player in Blender the materials are fine, but in Unity, it’s then which it becomes strange.
When i try to drag it into box it glows red and says uploads not available.
How do i upload images to the internet to use for this. I looked it up but i don’t want to add my pictures to a site where just anyone can view.
The normals might be reversed on the left arm - if you mirrored and didn’t zero out the scale and transforms.
Use anything to upload an image, dropbox, your own site, save a local image and upload, this shouldn’t be a hard thing to do for someone who has animated characters in blender. 
I too would bet that it is the normals that got turned inside-out.
That would result in you seeing the texture area from the back of the arm when you view it from the front. I want to remember that Blender by default displays meshes as two sided and this is why you don’t see it in the editor.
It is easily fixed in Blender; select the mesh of the arm and flip the normals 