Progesterone is a progestin, and since progesterone is an oily liquid, it is not easily absorbed after intra-muscular injection, the presence of hard lumps is normal, and the patient’s pain will be very obvious during the injection. If the hard lump does not disappear for a long time, you can use a hot towel on the surface to accelerate the blood circulation inside the muscle, you can try to make the hard lump eliminate faster. Progesterone injections are usually used in the case of fetal preservation, because the progesterone level in the patient’s body is relatively low, resulting in the possibility of pre-eclampsia and other situations, so it is necessary to inject external progesterone to raise the level of progesterone in the body; it is also possible to inject progesterone for pain relief when the patient is in great pain due to the presence of ureteral stones, because some studies have shown that progesterone also has a certain pain-relieving effect. Some studies have shown that progesterone also has some pain-relieving effects.