Your appointment is for the same health concerns which released you from your attendance at Sunday Mass. You would be dispensed from this also. In the future you will be able to schedule your appointments. For now, have peace of nind!
I will pray for you!
There is nothing to dispense from. (S)he was already dispensed from Sunday Mass. There is no obligation to attend Friday Mass, thus, no need to be dispensed from not being able to attend Friday Mass, and the Sunday dispensation does not therefore “cover” an obligation that doesn’t exist. The only way Friday Mass could need a dispensation would be if a holy day of obligation in your country fell on a Friday.
Moreover, I would submit that even if it was a holy day of obligation, a hospital appointment would
automatically dispense if it made one unable to attend Mass. There would be no need to seek a dispensation from a priest, nor any need to confess having missed.
From the CCC:
2181 The Sunday Eucharist is the foundation and confirmation of all Christian practice. For this reason the faithful are obliged to participate in the Eucharist on days of obligation, unless excused for a serious reason (for example, illness, the care of infants) or dispensed by their own pastor. Those who deliberately fail in this obligation commit a grave sin.
(my bold)
Therefore, for
serious reasons, one is relieved of one’s obligations without needing a dispensation. I live in a rural area and can only travel to Mass by car. If a snowstorm makes travel hazardous, and I stay at home, there’s no need to confess or call the priest for a dispensation. I use my own judgment. Similarly, if I have a bad cold or flu, I will stay at home, recognizing that for some frail people with compromised immune systems, what is simply miserable for me can be potentially dangerous for them. No need to obtain a dispensation or confess. If you’re elderly, infirm or cannot drive and cannot find a ride to Mass, no need for a dispensation; if you’re a minor and your
parents neglect your obligation, the sin’s on them, not you . There are many legitimate excuses, even including no priest available in your area.
Also missing has to be
deliberate. The car breaking down on the way to Mass, or missing the bus because one didn’t remember the schedule correctly, is not
deliberate.
On the other hand, a couple of years ago I rode in a charity bike ride to raise funds for cancer research. It was a two-day, 180-mile ride over a weekend, and thus no opportunity to attend Mass. Since it was for a good cause, I asked my spiritual director (a priest of course) for a dispensation, and obtained it. Other good reasons could be travel, vacation in a place with no Mass (say a wilderness camping trip), etc.
We are expected to use our judgment!