That description of the old woman exactly matches the bedridden old woman in the 1941 story "Finger, Finger!" by Margaret Ronan.
It describes the mean, harsh bedridden old woman as "evil" and "bloated" with eyes hidden in flesh and mounds of flesh under the blankets. She is so mean that the reader does not feel compassion for her extreme disability and degraded condition.
It is told in the third person,and tells the thoughts and emotions of the new maid, Carola, only 16 years old, on her first day working there.
When she brings in the food tray, the old woman grabs and strokes her arm, and powerfully pulls her down. The old woman asks inappropriate, demanding questions about her lover, Donald, who comes up at the end of the day with a horse-drawn carriage.
The head cook tells Carola of all the new maids who acted queerly, left the job after one day, and one who committed suicide.
When Carola brings the evening dinner tray up near the end of her first long, draining, frightening workday,the old woman clamps Carola down toward her.
Those hands were very strong. One of them alone was quite capable of keeping Carola where she was.
The rest of the story from, when the old woman clamps Carola down, suddenly switches viewpoint. Now Carola is in bed, watching herself walk out the door to go meet her lover. The old woman in the new body nastily tells Carola in the old one, "You're not going to meet your lover, Carola. He won't ever know."
Just as suddenly there is another weird twist: Carola trapped in the old body screams that the girl stole her rings.The head cook (the girl's boss) shoves the girl into the old woman's bedroom, forcing her in there until the police come, keeping the girl's stolen body from leaving.
With them both trapped in the bedroom, the quite vicious old-woman-in-Carola's-body taunts the bedridden real-Carola about how she will never see her lover again, and spits on her.
The twist goes really fast; I think that Carola in the old woman's body knows what she needs to do, because she (in the old woman's body) has "nine hooked fingers" "hooked to fit a girl's neck".
Carola uses her strong hooked fingers to grab and choke the young Carola's body to death. So the vicious old woman is dead, in a body-swapped way.
Old bedridden Carola calls to the police as they are coming in, saying it's about time they showed up. Apparently the ring theft is the crime they were called for, perhaps to justify the murder in self-defense.
It was published in a French antholgoy, edited by no less than the redoubtable Alfred Hitchcock.
Edit: there was no ""Finger, Finger!" answer while I was typing, but once I hit "post answer", I then saw John Rennie's answer.