My millipede is swollen, what do I do?

[AyuSayuki]

Hey guys! I have a giant Oliver millipede, he is not very big, he is about 10-12 centimeters, yesterday I noticed that some spots were appearing on his butt, and today these spots are bigger And my millipede isn't moving, he's swollen like he's going to explode, I don't know what to do, I'm really worried, is he shedding his skin or dying? I don't want him to die...He is my only millipede, I have had him for 2 months, please help me save milo

 

[fcat]

Wait for educated responses but the worst thing you can do is handle it