Got a counter offer from my current company, need advice

So I accepted an offer from a new employer, but about 20 days later, the HR from my current company reached out and asked whether I'd be willing to stay for at least a year if they offered me more than my new employer. I told them I needed a day to think about it. Now I'm wondering if I should tell my new employer that my current company is discussing a raise with me and ask if they'd be willing to match or improve their offer. I definitely want to leave, I'm not learning enough at my current company and the new company is a startup and seems to be doing well but the thing is, I still feel like the new employer lowballed me. I accepted because I wanted to leave, but I don't think the compensation reflects what I'm worth. Would it be appropriate to bring this up with the new employer ? Like I don't have an offer in hand (because that would entail telling my current HR that I am inclined to stay and I don't want to lie) or do I lie because I want to be paid what I'm worth, get a concrete offer and then speak to my new employer?

Posted by /u/AdHungry3525 on r/jobs
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