Would this be considered a compliment or an insult?

Sounds more like a sales pitch than either of those.

I’m with @Seelix on that. Either that, or just really inappropriate and unsolicited advice.

I would say it would depend greatly on the relationship between the two parties. Dependent on that it can go like seelix or iamthemob said or it could be somewhat friendly beating around the bush advice

It’s only an insult if the person has low self esteem. In general, it is a helpful comment if from a friend or relative. From a stranger – way off base.

Insult is in the eye of the perciever. lol

That sounds a bit tactless, but…I had a friend once that was hyper sensitive to any threat of slight, real or imagined.
It was amazing how she could put the most insane interpretations on the simplest of words. haha

I’d say it depends on how long you have known someone and if they are prone to backhanded complements vs. a once in awhile moment.

Ditto @YARNLADY.

If it’s from a good friend, or someone you know has your best interests at heart, I think that was a very tactful way to tell you they know of a product that will help your skin even more.
Don’t take it as an insult.

It would not be a good thing to say.

If this was quoted from a sales clerk, it is intended as a compliment to get on your good side through empathy, and it is not stated as such very well. The conjunction, “but”, basically wipes out the first part of the sentence in the context they used it in. And the ending clause “it will work better”, does imply your skin needs therapy with the other product.

If it were from a friend, it is probably well intentioned as a compliment. They were hoping to tell you about something they have had success with and know you probably have your own skin care product. They have used this other product and think it’s the bomb, and hope to get you to try it also, no insult intended.

If it was from a smart alack, it was an insult and they should be thrashed with a limber, willow switch. :)

An unintended insult and a pitch [your skin is looking better but not good enough—try this]
If it is a friend, consider the possibility of the product, but if not, just blow it off.
If you are English, further remember the adage “An Englishman is never unintentionally impolite.”

Any time someone thinks I am cool and important enough to share their top secret weapon against anything makes me feel special! Take everything as a compliment and life is a much smoother ride!

It’s a compliment when they ask how you get your skin looking so good. It’s a veiled insult when stated as you said.

If they are trying to help, that’s a good thing. What if it was spinach caught in your teeth, wouldn’t you want someone to offer you a toothpick?

I believe it’s just a question.