what happened to my lips? they are dry and have red bumps. It was on one side of my lips then spread to other.​

Insulin is a peptide therapeutic used to manage type 1 diabetes, which affects more than 20 million people worldwide according to the international diabetes federation. a significant limitation to the broad distribution and use of insulin to treat type 1 diabetes is the fact that it must be administered by injection rather than orally. why is insulin administered by injection and not orally?