Even if no holes have formed yet, it still may need to be patched. If brought to a true professional, this can be done, with little or no evidence of a patch job. Also, if it's under the arm, it is even less likely to be noticed. If the damage is done from friction shear of wool on wool contact, usually the fibers have become weakened and will need to be patched. It is best to do it before a hole forms or it can turn into a sort of cancer where one hole turns into many, or the hole is only the tip of the real damage done. If you catch it now, it will be less work for the tailor, less cost for you, a less noticeable repair, and greater longevity of the garment.