My son woke this morning with swollen lips and said they were really sore. I put Vaseline on them cos they seemed dry and gave him antihystemine. I sent him to school but they were no better this evening. He's 5 and hasn't eaten anything unusual to my knowledge. He said he bit his lip yesterday but I don't know why that would cause both to swell? Could they be sunburnt? If he's not better tomorrow morning I'm taking him to docs.