I've only hung overnight twice. The first time I didn't know what an underquilt was, and I ended up in the house on the floor in the middle of the night.
The second time I was more prepared, and I'm pretty sure I didn't use a pillow, just leaned my head against the side of the hammock.
I'm going again next week and I think I'm gonna avoid packing a pillow. I'll report back ๐คทโโ๏ธ