Quote from @Elizabeth Conklin:
Quote from @Kevin Luttrell:
Just curious, how did you determine that your credit score dropped from this HELOC? What are you using to monitor your credit? Credit Karma?
There are many different credit scoring models out there, and even the most prevalent scoring model, FICO, has multiple different versions that calculate your scores differently. 
I’ve noticed credit utilization has a much greater impact with the vantage score model (Credit Karma) than the FICO models that most lenders use. So when I rack up my line of credit I see my Credit Karma score drop 100 points, but then when my credit is checked for a mortgage it’s still just as high as it was before I increased the line balance.
Thanks, Kevin. Score showed up through FICO. So I will check-just want to make sure this is not an impediment for future credit.
Credit scores are tools, not trophies.
No one gets approved on their score. Your score can get you declined, however. In a way, it's a "gatekeeper".
I'm thinking there are two factors at work here.
How old is the HELOC? New accounts cause a ding on your score until they age a bit. They also impact your average age of open accounts, a scoring item for both FICo and Vantage.
... and yes, you will take a hit on credit utilization. A HELOC, while RE-related, is still a revolving account. So, two things to check:
1. What is your total revolving credit utilization?
2. Is your HELOC being properly reported as RE-related? Some lenders get this wrong from time to time.
The other respondents have correctly pointed out that income is *NOT* a credit scoring criterion. Your lender may, however, consider it when deciding whether or not to extend credit (DTI).
My $0.02 ...