Ahsan Allahu ilaykum: someone put two bandaids on side of heels (and they are waterproof), not for injury but to prevent friction pain with a certain shoe. However she forgot to take it off and made wudu , prayed isha and fajr. Does she repeat those prayers?

A waterproof plaster put on for comfort and not for a wound is not a jabirah, so the water did not reach that part of the foot. Imam Ibn Baz was asked about a woman who prayed a whole week having forgotten a covering on her feet and said she removes it and repeats the wudu and the prayers, and forgetting lifts the sin from her, not the repeating.