Hello. Our baby is teething; the teeth aren't quite emerging from the …

Hello. Our baby is teething; the teeth aren't quite emerging from the gums yet, but they are moving within the gums, and it's clear that by evening the baby is in a lot of pain, becoming very fussy and sometimes even hysterical. I can give Nurofen a couple of times a week at night. I've been doing this for 2 weeks, every 2-3 days, and sometimes several nights in a row, up to a maximum of 3 nights. Is this harmful? I've heard that it can be given every 6 hours, but I don't do that. How long can I safely give Nurofen without causing harm by doing it this way?