hrmm I personally have never dealt with SBD in aquarium fish, but it does seem like that could be a possibility. I would definitely keep trying the pea in case the SBD problem is a symptom of constipation. Does she have a swollen belly?
I heard you can also help her by lowering the water level making it easier for her to access oxygen.
um perhaps you should do some research, I have read that some people salt bath with aquarium salts if bettas don't eat the pea, but again, I really have never had a betta with this issue yet.
I just read that from this article http://www.petfish.net/articles/Bettas/constipation.php
perhaps you should ask another member if this article is a good reference