CREATE TABLE seguidos (
segi_id         int         PRIMARY KEY         AUTO_INCREMENT,
segi_nomSeg     varchar(50) NOT NULL,
per_id          int         NULL    UNIQUE,
segs_id         int         null,
FOREIGN KEY (per_id) REFERENCES perfil(per_id) ON DELETE CASCADE ON UPDATE CASCADE,
FOREIGN KEY (segs_id) REFERENCES seguidores(segs_id) ON DELETE CASCADE ON UPDATE CASCADE
);

Error Code: 1553. Cannot drop index 'per_id': needed in a foreign key constraint

Error Code: 1091. Can't DROP 'per_id'; check that column/key exists