Dewgong any experience using as attacker?

dewgong is the poor mans lapras. no real point in using the dewgong unless you like challenging yourself. base stats and moveset are more important than IVs.

you could still have the dewgong as a dragonite attacker if you've left your lapras at a gym though.

Androgynous is right, even though i can confirm that dewgong is a neat dragon killer, i got one similar to yours but 1802 cp and i love him... but ye, i dont have a lapras

If your live in an area full of Dragonites then yes, you should power it up. It has the best offensive Ice moves and your Lapras (while being a beast with that IV and set) won't kill all the Dragonites on its own.

I have a Lapras, a Cloyster and a Dewgong for taking down all the Dragonites in my town (there are a ton of them). I LOVE using Cloyster tho

As long as you have to much stardust then you should power up your Dewgong, IV doesn't matter much here but it has a great moveset for attacking. Blastoird, Slowbro, Golduck with Ice move are all good Dragon killers.

Your Lapras should be enough for Killing 2-3 Dragonites. I would keep it for that and not put in a gym.

Plus dewgong works well when you fight a random Dragonite but when you face a real defender SteelWing/DragonPulse with 2900CP+. You will have trouble with your dewgong.

That Dewdong can come in handy training gyms. In 6 months you may have a low CP Lapras to use but for now its an adequate stop gap measure.