right thumb blister | Golf Monthly

My consistency & scores are gradually improving, yesterday I was one topped tee shot from breaking a century for the first time, double figures on any hole are relatively rare, and I can now go & play different courses without feeling too self-conscious (well, after the first tee shot anyway – one day I’ll be able to enjoy that shot!).

However I now have a blister on my right thumb – a quick google of ‘golf right thumb blister’ brings up several thousand results, basically telling me that’s terrible abandon all hope.
Does anyone else get a blister there?
Is the cause gripping wrong or gripping too tight? (or both!?)

I know the recommendation is likely to be see a pro, but tbh I was a little disillusioned with what I was getting for the dough and with time & money at a premium have decided to play as much as I can until winter when I will pick up lessons again somewhere else.
Thanks for any advice!