Yes, you can use it for yourself in the same room or to place a steaming bowl with a drop next to the piggies if they have a respiratory issue, at least until you have seen a vet.
However, piggies don't normally pick up a cold or flu from humans. Their respiratory illness is bacterial, not viral. There is comparatively little that can cross over between rodents and humans.
Here is our information about transmission issues and tips for when you are ill:
Contagion - Inter-species Transmission and Pet Care During Owner Illness/Pregnancy (incl. Covid)
I would however recommend to inhale in another room before you go to bed (helps to clear your nose and ease your breathing for going to sleep) and once you have got up in the morning to help clear your respiratory system of what has collected overnight. And continue to do so as often during the day as necessary.
Make sure that you drink plenty and top up on vitamin C. Chicken soup (unless you are meat-free) can also help speed up recovery.
I hope that you are feeling better soon.
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