Lice in a dream are traditionally read as thoughts or worries that cling and are hard to shake, and as a fear of being judged as unclean or unwanted. Because they live in the hair, close to the head, dream books tie them to nagging ideas and to people who take a little from you without asking. Finding lice on yourself is read as embarrassment or the sense that something small has got out of hand; combing them out as the wish to be rid of it and start clean. Lice on a child or someone close are usually read as worry on their behalf. Notice what in waking life keeps itching at you, however minor it seems.
Has this come up in your dreams before? What was going on in your life then?
My Cosmic Code has a private dream journal. Write a dream down and the app picks out the symbols in it, shows what dream books say about them and, over time, which words recur across your entries. The journal is stored on your device only.