1. It is permitted to remove a thorn or a splinter (as of wood
    or glass) on Shabbos even if there is no reason to believe that it endangers
    life. This may even be done with a needle because it is not clear that
    removing the splinter will cause bleeding. Even if it would, because the
    splinter is deeply imbedded, it is permitted to remove it with a needle if
    there is no other way because the removal of blood would, in this case,
    involve the violation of a rabbinical rather than Torah prohibition, and the
    rabbinical prohibition does not apply where a person is in pain. While
    removing the splinter, a person should be careful not to remove any skin,
    which is forbidden because it removes something from it’s place of growth.
    (It seems that where it is clear that removing the splinter will cause
    bleeding and the person is not in great pain and Shabbos is almost over,
    removing the splinter should be postponed until after Shabbos because there
    are poskim who hold that it is forbidden to remove the splinter when it is
    clear that removing it will cause bleeding. )

  2. There are some who hold that a splinter under the
    fingernails and a splinter that penetrates a vein can be dangerous and, for
    that reason, may be removed even if doing so involves violating the Shabbos.
    And it seems that if a person has had the splinter for a while and we can see
    that it has become infected, it is also permitted to remove it.

  3. It is best to use a needle that is not ordinarily used to
    do something forbidden on Shabbos, such as a safety pin. But if the only
    needle available is a sewing needle or some other needle that would ordinarily
    be used to do something that is forbidden on Shabbos, it is permitted to use
    it, for a tool or utensil that is used for work that is forbidden on Shabbos
    may be used for other purposes on Shabbos.

  4. The needle should not be sterilized by holding it in a
    fire. Rather, it should be passed through a flame or, even better, cleansed
    with an antiseptic.

  5. If a dangerous object that is muktzeh on Shabbos,
    like a needle—even a broken needle—broken glass, matches, medicines, a
    knife used for shechita or circumcision etc. is found in a place where
    there are children, it may be taken and removed.

  6. Since the Torah forbids a child from causing his parents to
    bleed, a child should not remove a splinter from his father or mother unless
    there is no one else to do it and his parent requests him to do it. In that
    case, it is permitted to remove it even if doing so will certainly cause
    bleeding. The child should ask his parent to forgive him if he makes him
    bleed.

  7. It is permitted for a child to shave his father or to cut
    his parent’s nails because, it is not likely that doing so will cause
    bleeding. If the parent has delicate skin, so that cutting his nails will
    cause bleeding, it is forbidden unless there is no one else to do it and the
    parent requests him to do it. In that case, the child should ask his parent to
    forgive him if there is bleeding.

  8. Although a person is obligated to honor his grandparents,
    his parents-in-law and his older brother, there is no specific Torah
    prohibition of causing them a bleeding wound. Therefore, there is no reason
    for him to avoid removing splinters etc.
  9.