Lump in arm 2 months after vaccination

[PlopButNOPudding]

My dd (3) had a infanrix -hexa booster 2 months ago.
Immediately after she had an angry red lump.
The redness went away within 6-8 days and left a hard lump the size of a golfball around the injection site.
I took her back to the doctor and they said whilst not common, it happens and its nothing to worry about and should go.
2 months later the lump had gone down but is still very hard and the size of a pea.

Has anyone on here experienced this? Should I be worried and seek a second opinion? What about other vaccines and further boosters of the same vaccine (she is due one more). It didn't happen with the first 2 shots, I guess I'm worried about worsening reactions.

I would have it looked at again. It is very well possible that it just takes a bit longer to go away (DD had a lump in her leg from her DTP/hib that needed over 2 months to go), however, in rare cases, a small cyst forms at the injection site which might not go on its own - an ultrasound would show whether that is the case. Good luck and let us know what it was!

Thanks for your reply- I'll update when I've been back to the doctors..