AITA for telling my BF that I liked his tattoo?

For a couple of weeks before the incident, my (F19) BF (M23) has been searching for ideas for finger tattoos that would complement the videogame themed one that's already on his hand. He also asked me for my opinion on several of the ones he found on Pinterest, which I obliged and told him which of them I thought would match his hand tattoo best from an artist's standpoint. (For context, I'm an artist myself and frequently draw fake tattoos on him so he thinks that I'd be a good person to consult.) After several weeks of deliberating, he spoke to his tattoo artist about what he'd like done, to which the artist said he would play around with freehanding the design as he had a decent idea of what to do (he's the same artist that did the original hand tattoo.)

The day of the appointment arrives, and I accompany my BF to the parlor. The artist sketches out the tattoo on BF's hand, and BF waddles out and shows me the design. To me, the design looked awful, but I didn't have the heart to tell him that. He looked so excited and happy, and even said that he gave the artist an idea for an addition to the tattoo mid-sketch. He asked me what I thought, but seeing him so giddy and excited, I decided to keep my opinion to myself, since it wouldn't do any good. I said it was cute and that it resembled the flooring of a retro arcade, leaving that up to his interpretation.

He got the tattoo done, and we went home. He also posted a photo of said tattoo and got many compliments, which boosted his mood and made me feel like I'd done the right thing by staying quiet. He kept badgering me for my opinion on the tattoo every few hours, and I kept sidestepping the question. But at some point, when he asked again, I said that it wasn't my favourite of his tattoos, but I'm glad he was happy. He then started to question me about why my response changed. He asked what I didn't like about it and why I wasn't honest much earlier while we were at the tattoo parlour. I answered honestly and said that I didn't like it for such and such reasons and that I wasn't honest because I thought that telling the truth wouldn't do much good. He then continued to tell me that I should have been honest rather than sparing his feelings. Even after that, he still seemed content with the tattoo and said that my opinion wouldn't have swayed him out of getting it, which only enforced my reluctance to admit my opinion.

So, AITA for not saying that the tattoo was not aesthetically pleasing to me?