Well I know the problem! After 42years you can imagine how bad it is with my venes. The first 18 years we used only the two on the left side (elbow) and they are damaged since 25 years now. Useless. The trick is to have at least 3 possible targets and rotate so if you use one today it would have about more than a month to restore…try to keep her well hydrated and warm clothes because cold narrows the veins. The other thing is to use very small veins for the type & cross which are not suitable for transfusion like on the back of the hands. And finally a hand-cream with marigold Blum could be helpful.
Hope it helped,
Take care.