It’s gonna take a LOT of berries to make some juice, though!
Mom used to make elderberry jelly when I was a kid.
We beat every road ditch in the county harvesting the berry clusters. There wasn't enough calamine lotion on the planet to make all of the chigger bites I got stop itching.
I hope you saw the posts earlier about use of Plantain for insect bites and itch. The didn’t mention chiggers, but did mention wasp sting and mosquito bites.