I've noticed the same thing. I've been meditating daily for many years
and do a healing/releasing type of meditation. I find that a castor oil
pack on my stomach just plain releases foreign energy from my body - all
over. I've also learned that if I do it two, three or more days in a row,
the second and following days are not as healing as the first day. There
has to be a build up in the body that that castor oil releases. I find
that the same thing happens if I apply only a small pack to my knee or
leg. Have had that happen several times.
Castor oil is also know as Palma Christa, or the Hand of Christ. I
believe it. It has healing properties far beyond what we recognize on a
body level, and I don't think that any of it penetrates the skin.