The thing with Saturn herbs is, they're not necessarily indicated just because Saturn is strong in your chart and/or you're having a significant Saturn transit, and in most cases, they should not be used without other types of herbs to balance them. Saturn's qualities are cold and dry. Saturn herbs are considered Saturn herbs because they have cooling and drying qualities. Whether you need cooling and drying qualities in your herbs, and to what extent, depends on your constitution and on what kind of condition you're treating.
If you have a cool and dry constitution to begin with, cooling and drying herbs are generally not what you want, because they would make you even more cold and dry and even more out of balance. If you're treating a cold and dry condition--that would be something that constricts, like, for example, migraines--you usually want different qualities in the herb(s) you use. And if Saturn herbs are indicated, you probably also want some with moist and warm qualities to balance them.
What you've described sounds like a hot condition--expansion, swelling--which may be dry or moist, depending. So, possibly, Saturn herbs are indicated. And some of what you've picked sounds like the right thing. Nettles (which are more associated with Mars) are good for histamine reactions--they balance histamines and calm allergies--and for arthritis (although they're usually used externally for full-blown arthritis). Yarrow is good for skin conditions of all kinds. Together, they clear the blood (nettle) and the liver (yarrow), which is likely to be necessary if you have a skin problem. Both of them are highly safe herbs: not toxic at all, except in doses much higher than anyone would ever, realistically, want to take.
But, I can't give you solid herbal advice just over the internet. There are far too many variables in finding the right herbal medicine. If you really want to go the herbal route, best to work with an herbalist in person.