What can I do ?

I’ve had box braids twice now and absolutely loved it, but my scalp seems to hate it. Everytime I’ve gotten them done, I get tension bumps, regardless of how loose they are. The first time I had them, I did them myself, so I left the ones on the very edge of my hairline really loose bc I knew my scalp is sensitive to styles like this, and I still got tension bumps. The second time I had my aunt do them, and she knows I’m tender headed ( she would braid my hair when I was younger) so she knew not to make them tight, yet still I got bumps. What could it be? What can I do fix it?