My little boy is seven months and we're having a really bad few days teething I can feel them coming through so think he's actually cutting two.
When he was 3 months he had a week of pain and his gums really hardened during that time we used ambesol liquid throughout the day and calpol at night. He couldn't get the hang of teething toys at all or hold them properly as he's small.
We've got a cheeky chomper bib he will use and found it handy he can't drop it, he's not taken to any of the nuby teething toys we've got loads he much prefers shoving one of our knuckles in his mouth while having a cuddle.
Also rate the Aston's powders however didn't find them useful until over six months when the amount they can have significantly increases
Detinox gel is working better than the anbesol now too so I'd say give it a go as it's from birth
Teething is bloody horrible, I was up in the night last night with a very upset baby saying to husband I wish I could have toothache for him!
When they have a virus, temperature etc you give every day until it's gone even when going to the doctors if it's viral it's just paracetamol and ibuprofen recommended for a few days or even a week.
Don't be scared to give pain relief when you know your child needs it, I've found teething worse at night so use the liquid, gels, sachets, toys and distraction through the day then calpol at bed time.