I thought "exploding" might be somewhat exaggerative to use in this kind of situation. But is it common to say in this way?

Native speaker’s answer
Rebecca
Yeah, it is common to use "exploding" in this context! If you have a very painful headache, then you can say that it's "exploding." Ex: I have an exploding headache. Do you have any painkillers? => used as an adjective Ex: I need to go lie down. My head is exploding!