i've only got a few bits and piueces i can show you on comfrey, i would go into your local health shop, prefrably an indepentant one where you may get more well-informed advice than somewhere like holland and barrett.
"comfrey contains several potentially beneficial substances that may be applied to the skin. Generally, it has high concentrations of allantoin, a protein that encourages new cells to grow; rosmarinic acid, which is known to be anti-inflammatory; and tannins, that help to firm skin tone. Because comfrey also contains mucilage, which swells in liquids, it forms a soft, sticky covering that stays in contact with the skin. All of these properties make comfrey useful when applied topically to soothe and treat bruises, minor skin irritation, and sprains. Comfrey may also have slight pain-relieving properties. It should be used only on unbroken skin, however -- not on large or open wounds. A mouth rinse made from comfrey may have some benefit in soothing sore gums and throat, but care must be taken not to swallow it. The mouth should be rinsed thoroughly with plain water after a comfrey rinse has been used."
"Comfrey has a long history of use as a topical agent for treating wounds, skin ulcers, thrombophlebitis, bruises, and sprains and strains.1 2 Comfrey was used by herbalists to promote more rapid repair of broken bones, hence the common names boneset and knitbone. Topically, comfrey was also used to treat minor skin irritations and inflammation."
if I have time at work tomorrow i will try to find some more info.
the one i would ask for, if oyur health shop sell it, is "Biofore comfrey sports gel" (not bioforce comfrey cream which is for wrinkles and face!)