The six-week-old cub was found weak and lethargic in Llandysul in January, and weighed just 919 grams.
She was fed through a syringe and looked after by RSPCA officer Ellie West, before being transferred to a pen owned by a local badger group.
She will now be moved to a wildlife centre for at least a year before being returned to the wild.
Ms West said: "It was really touch and go for this poor otter cub, who was in a desperately sorry state when I rescued her.
"So much energy and emotion has gone into helping and rehabilitating her, and - thankfully - she responded well to being hand-reared.
"It is hoped we will be able to return her to where she belongs - the wild - sometime in 2018, which would mark an amazing turnaround from when I first rescued this cub in Llandysul."
An otter cub in a "desperately sorry state" rescued in Ceredigion has been hand-reared back to health.