I had one with my first birth - my son was born face up instead of face down (a posterior presentation) and it tore me hideously. The hematoma was in the absolute worst spot, toward the anus, and I could hardly sit for ages. I mostly kept a cold rag on it as much as I could and used Arnica gel (it's an herbal remedy I found at the Dollar General of all places). It didn't help with the pain, but there's a spray analgesic you could get from any pharmacy that might help a little (I guess it depends on if the hematoma is on the outside or inside - mine was just on the inside, but I could reach it to put the gel on it).
My experience didn't worry me - I didn't even think of it - when I got pregnant the second time, but I ended up having a weird complication that was caused (we're pretty sure) by that hematoma. In that same spot where the hematoma was I ended up having what the midwife was calling a varicose vein. I phrase it like that because it didn't FEEL like what I imagine a varicose vein would be, but anyway, that spot got enough pressure put on it by my huge belly that, esp. when I'd stand up, it would fill up with blood and protrude out, like a gigantic tick. Now THAT was uncomfortable! LOL I don't know, and the midwife (or the OB/GYN) didn't know whether that was caused directly by the earlier hematoma, but we do know it was already a weak spot for me. Plus I was pregnant with twins - TONS of extra weight pressing down! Anyway, good luck - I'm sorry you're in so much pain. They said it was okay for me to take ibuprofen, that it didn't cross the barrier into the breastmilk, and it helps take the swelling down as well as helps with the pain, so maybe try that (your husband might know about that too, being a nurse).